I'm curious. Why does everybody hate him?
Why do I think he's great? It's simple: He's the one pilot that has a very good chance of one-shoting a X-Wing. Yes, I mean it. One-shoting a 5 HP Modell with 4 attack dice. His ability is HUGE. If you're not dealing 2 damage with one crit you can choose one devastating crit for one opponent, making him mainly useless.
Give him Marksmanship (imho the one pilot that can actually make use of it), a concussion missle and a free action from Howlrunner with Squad Leader and he will be a nightmare for every opponent. In my eyes far more dangerous that Wedge.
I have been summoned.
Maarek Stele sucks. His ability doesn't come up often enough to be good by itself. With Marksmanship, his odds of landing a crit are much improved but then his total cost is 30 and he still isn't as good as Vader. Yes, he does have an improved chance of one-shotting an X-Wing will a concussion missile but the improvement isn't that great.
Here is a set of charts to illustrate what I'm talking about:
(Interestingly, in the process of making these charts, I've dicovered that the data table most people have been using to determine damage has an error but that is outside the scope of this post.)
Here we are looking at a Concussion Missile fired with Marksmanship. I've treated and crits as the same for the top sections of the chart because figuring out the total number of crits that will happen is overly tedious. For the sake of argument, some of the calculations at the bottom assume that 2 crits get through which is the best result anyway.
In the sections labled "MarksConc vs. 2" and "MarksConc vs. 2f", I show the odds (in the right columns) of getting a certain number of hits (in the left columns) when shooting a concussion missile with marksmanship against 2 defensive dice and 2 defensive dice with a focus respectively. Remember that this section is treating hits and crits as being the same.
In order to one-shot an X-Wing, Stele will need to land 4 hits because the first 2 damage will be absorbed by the shields which leaves only 2 hits with a chance to crit on the hull. As you can see, Stele only has a 28.8% chance of landing 4 hits on an unfocused X-Wing and a 10.4% chance of landing 4 hits on a focused X-Wing. This is before taking into account the chances of landing a direct hit.
The sections labeled "Direct Hit Chance" just show the chance of drawing at least one direct hit card when landing 1 or 2 crits with Stele's ability. For reference, the chance of having a crit be a Direct Hit for a normal pilot is 21.21%
The sections labeled "Chance of 1 Shot" show the overall chances of one-shotting an X-Wing when 2 crits or 1 crit show up. The left section shows the odds against 2 defense dice and the right section shows the odds against 2 focused dice.
Let's say that whenever Stele gets 4 hits to land 2 of them will be crits (in reality, there won't always be 2 crits); if that were the case, he'd have a 21.9% chance to one-shot an unfocused X-Wing because he only lands 4 hits 28.8% of the time and he won't always be able to get a Direct Hit card. When attacking a focused X-Wing, his odds drop to 7.9%.
Even at 21.9% (which is a higher chance than possible in reality), the investment in points is too great. If it doesn't work, you are stuck with a super expensive TIE/ad that doesn't have any extra defensive ability. The Marksman ability will help him land crits, but using it means he can't focus or evade. You want to use Howlrunner with Squad Leader to give him an extra action? Then Howlrunner isn't focusing or evading and that is an investment of even more points.
Stele costs almost as Vader but his ability only works when he crits and even then there is no guarantee he will get a Direct Hit card. A crit is worth about 1.2 points of damage for normal pilots; for Stele, crits are worth about 1.5 damage. When vader uses his ability to increase his attacks, the damage increase is generally between 0.1 and 0.2 per attack regardless of how many crits land.
Vader is a much better pilot for the cost. Even when Stele is using Marksmanship, Vader still does comparable damage and Vader's ability has much more utility.