Happy to help out by talking about stuff, I should underline again that I'm not even semi-official here. I'm just another forum user that happens to know more than you - and can't say everything! Anyway, but here's my thoughts.
Reactions/ turn sequence:
I'll be honest - I'm not a big fan of alternating activation systems personally. I feel as if when you get more than a handful of activations (i.e. three or so units) it produces a sort of fractured game flow where each player naturally gets drawn into thinking only about the next activation. I like games where units can coordinate their efforts and the controlling player can work to an overall plan. Reactions keep the opposing player involved, and rather elegantly handle the kinds of interplay that can be gained from straight up alternating activation systems. There is also nothing at all wrong with having the time to make a cup of tea.
Flexible army lists and a degree of customization are something that I think miniatures gamers tend to expect from their rules and are some of the most fun parts to write. Army lists can also have a key function in keeping forces balanced through other means than raw points values so that the tank thruinge doesn't become the only viable option. I've been working closely with FF on this particular topic in relation to the currently available Dust Tactics models and what's coming up for the future so that hopefully we can put some lists in the core rules. Personally I'm also hoping to see some dedicated army list books in the future as more factions become available (SSU!) but that is entirely a pleasant pipe-dream on my part at present.
I've been working closely with Paolo Parente (who is a lovely, lovely man btw) on the background material produced for Dust Warfare and he seems very happy. For the core rulebook most of what's been added is what you might expect - world war overviews, weapons and unit descriptions etc. How much of this FF can actually fit into the finished core rulebook I don't know, but having worked with them before I know they like their background.
Relation to Dust Tactics:
One thing I should make clear is that the decision to follow Dust tactics so closely comes from me, it's not like its something being imposed by FF or anything. Looking at the core mechanics of DT I saw something that was well fleshed out, nuanced and distinctive, so much so that I liked the idea of developing it up into a tabletop game that was the same-but-different. Dust Warfare adds a fair bit granularity to the DT formula and completely changes the turn sequence meta-game, so I wouldn't say they are the same game by any stretch of the imagination. I can't help but think that the benefits that could be gained by breaking the two into very different games are outweighed by having a set of core mechanics that are already known and understood. Widening the pool of potential players is a huge benefit and it pays well to never, ever understimate how important that is to ensuring a game takes off. Quite aside from all this, it means we'll never be in a situation where a released model can't be used in DW.
Real world tanks:
This comes up a lot, I've taken a look at the player generated cards for DT that are hosted here and noodled around with a few stats for things. It's something I'll pursue with FF but I'd be surprised if stats for Shermans make it into the core rulebook, probably more of a web site thing if at all. Keep in mind that from from the perspective of running a business that sells models this is, strictly speaking, a bad idea. There's plenty of hobby-based arguments for it, certainly, and we'll be talking about it, but no one should be surprised if FF don't bite. If the worst comes to the worst I'll be happy to help out with establishing some fan-based unofficial stats somewhere that we (and when I say we I mean I) can agree on
That's all for now, folks, hope that helps.