Most of the Thor hate comes from a vocal minority of players who play strictly solo and simply declare him bad rather than "bad at solo" (and there is a fair amount of legit complaints about him being poor at solo also). But there are actually more players who think positively of him, but those comments don't stick out like hater comments.

And there are those that think quite highly of him
https://thesidescheme.wixsite.com/thesidescheme/post/high-fives-hero-aspect-combos

But yeah, if you play to his strengths, he is very strong, its just solo by it's nature, forces you to rely on his weaknesses. And this game does have a large number of solo players, especially among those that frequent online social channels.

But there is no arguing that he is a very divisive hero.

We beat this without using caps.
 
And no, that's not the only way to succeed.

We beat this without using caps.
 
And no, that's not the only way to succeed.

We succeeded against the scenario, albeit we only got to play it once.
 
One of the big deal, i think, is that we had my wife playing the Canoness (she always does) and another player got the Navigator at random. Both those can toy a bit more with corruption than other characters, so this may explain our success.
 
Obviously, with a Nemesis on the board, the scenario is completely nuts as mentionned above, and i wouldn't introduce a nemesis unless there was 5 characters already. The scenario is co-op for a reason.

Well like I said before, I am always happy to draft this team and it might even be that it's my favorite one as well. This being said, I do not win every game I play with the Dark Elves, but they are always a good contender for the pole position on the fan track.
But yeah, there is no auto-pilot function with the Dark Elves like there would be with other teams like Humans, Undead etc. You cannot sit with 2-3 highlights and a tournament thinking that you have a decent shot at winning all of them just by using the players in your hand. With the Dark Elves, you really need to go all-in for the rewards you truly need. Obviously there will always be cases when committing one single lineman to an empty spot will earn you an easy reward, but most of the time I tend to pack my Dark Elves together and thus try not to be everywhere at the same time (bearing in mind we have 5 highlights and a tournament in our games).
I think the Dark Elves have unexpectedly decent odds against the top-tier teams. Mid/low-tier teams need to go all-in in order to compete at all, so psychological warfare doesn't really apply against them as they need to go for the easiest target, which you often are due to your overall low star power. Against top-tier teams however, the Dark Elves are in a very particular position. As opposed to mid/low tier teams, top-tier teams always have a choice to make in order to make the most powerful play they can achieve in the situation. This is where your players are seldom the prime target (unless you're winning already) because using a 4-5 star power player to tackle your star power 2 player and get a backfire in response is not necessarily “the best play out there”. I digress a bit, but I think top-tier teams seek each other out in this game, leaving some room for other teams to try and compete. If I play Humans and a buddy of mine has the Undead then I would try to limit his capabilities as much as possible instead on focusing on a team that has a lot less chance to fare as well as ourselves. So yeah, I would try to commit players to match ups against these teams early in the game and try to avoid Chaos, Goblins, even Orcs and Vampires as much as possible in the early stage. Wood Elves are a good target because they are good to tackle (this said they are not top-tier in my meta).
Then regarding play style. I think Dark Elves need to be played very aggressively. By this I don't mean that you’re going to tackle anything at any range, but that you want every skill to count and force your opponents to make bad decisions by using the downed skills or the team upgrades to your advantage. I actually think that a passive opposition is almost worse for the Dark Elves because they cannot compete based on star power alone, so you won't win match ups if all you do is pile up players in front of an opponent doing the same thing. You need to tackle players, and be tackled in response. You need to trap their attention.
How to use the players in the roster is key to that. A few thoughts about the things you mentioned, is that you WANT the runners to be tackled. I really think the 2 star power is great because it incitates your opposition to bring them down. And if they do, dump off the ball and cycle a card. You need that sprint skill. The way I use Assassins is that I commit them to match ups with an interesting enchanted ball so that if I miss the tackle then I can grab the ball and execute another skill. I nearly always go for the cheating token when I commit Witches or Blitzers, unless I don't think I can lose the match-up I commit them in.
About the downed skills, I agree that you don't have full control of those since they rely so much on your opposition choosing to tackle the player with these skills. But I truly believe it's more powerful than you think because there aren't many coaches out there that want you to strip them off the ball, get a potential +3 power cheating token or cycle another card. So yeah, they tend to leave these players alone unless they are star players with great influence in the match up they're in.
I think some coaches are overly defensive in games like BBTM and try to be consistent from the beginning to the end. I don't think this type of strategy pays off very well with the Dark Elves. I would really not be too afraid of tackling stronger players, and committing players to match-ups against top-tier teams. I would grab a cheating token for my split skills players, and so on.
About upgrades and how to make choices for the match ups you need to commit players to. The star players deck for the DSS provides plenty of resources for the Dark Elves so that's what I tend to go for first. The star Vampires are really good for the Dark Elves. As always, I tend to get rid of my linemen as I draft non-freebooter players. Now the thing is that drafting big fat players automatically makes you more of a threat to everybody especially in tournaments. Which is why I tend to time/delay these star players the best I can (unless said player is the only sprint player in a hand full of linemen) to allow the core of my team to operate in the dark (like I said, good players choose flashy and juicy targets) until I can slam them into play and win on the spot.
Now this is where I'm not 100% sure what the best approach is in terms of payouts bar star players which you're going to need anyway. The “safest” approach brings your team in pair with the other ones quicker, at the price of competitiveness for the things that make Dark Elves so tricky to play against. You would typically go for staff upgrades and try to get a set of coaches and a few scoreboard phase abilities that allow your fan track to stay high. That's not how I play though. I usually go for the team upgrades and no staff upgrade at all. I mean, a staff upgrade is always a good thing, but I always strive after getting all my team upgrades. The team upgrades for this team takes the things I just described and help you making these as relevant/succesful as possible. Death lace in particular is a game changer ability. Dark Sorceress strips the ball off players who can't drop it by normal means etc. Dice re-rolls, double tackles etc. I don't know, I always find a use for these abilities. I would gladly trade one of the weaker ones for a sprinting coach, but that's not exactly how it works heh.
Anyway, that's how I set my mind when I play this team. From there **** can hit the fan anytime, especially under the Foul Play rules

They can easily pick the theme of a Lustria expansion with Lizardmen, High Elves and Amazons.

Downed players lose their abilities, however, so Dauntless is useless in this case.

So far here's what we're doing:
 
Undeads: we've found them head and shoulders above the competition. As my wife stated, she doesn't even have to think to win, even on her "first player" turn.
 
1 - Undead mummy gets 1 Tackle, not two.
2 - Ghouls get Sprint/Pass instead of both
 
Vampires:  The bloodlust counters mechanism fail to provide the team sufficient power to make it useful.
 
1 - They start with the Force of Will team upgrade.  A variant of this has them starting with Subliminal advertisement, in order to emulate their tabletop ability to break through cages with ease.
 
Dwarves:  Many threads say they are some of the hardest team to win with. We believe it's not the weakest team, but rather its lack of the sprint skill prevent it from recovering from a bad hand.
1 - They start with the Rigorous Training team upgrade. This makes their unique access to Guard far more desireable, and an actual reason to use it with the Blockers.
 
Dark Elves: We're at a loss here. Despite this team having the most time played in our group, it's performing poorly almost every time except on sheer stupid luck. The team suffers from having very low power value overall (only 4 players at *** ), almost forcing it to gamble the game on 1d blocks, which is further tempting luck to fail horribly.
 
Their downed skills should provide a relief, since they are going down often, but the loss in star power value is too great, they end up loosing the match ups. Facing any of the high tier teams make this flaw very obvious.
 
The witches and blitzers are fine, as are the linemen, so obviously the trouble is with Assassins or Runners. We've not been able to pin down a team upgrade or other modification that would make this team less of a pita to coach.