When are separate difficulty sliders for the campaign and battles coming back?
Will buying the game now get me a crippled version that's missing an entire faction?
Does CA throw a hissy fit if I get my steam key from g2play or similar?
Those are my main concerns before buying.
Separate difficulty sliders ARE in. You can even change the Battle difficulty at any time from the options menu.
Speaking as a steam user, despite pre-ordering I didn't get the Hattori faction... though I did get some TF2 items that are waiting for me. I haven't seen anything that makes them particularly worth worrying over.
I'm not sure about #3.
The extra faction was a 'limited edition' bonus. Despite this being a
Steamworks game, the Steam release of said game was
not the limited edition; only 'selected retailers' got it, and Steam wasn't selected.
That said, you instead got Genuine-quality TF2 items. Even if you don't give a rat's arse about TF2 items, there are lots of collectors who apparently
do. I heard about one person who managed to sell his Genuine items for ~$20, and another person who got almost $50 worth of games gifted to him for his loot. So, yeah, one mostly-useless faction and one extra historical battle, or the ability to make the scum of the TF2 community drool on command.