Equal rules would be nice, but I'd also like it if they took some ideas from the Long War mod and brought them in. Namely, the different classes/upgrade trees, class specific items, the new tech levels, and number of starting locations. Not a big fan of the fatigue system, though I understand why the maker added it in. I also like Long War's officer system, though I've heard he's changing how officers work in beta 15e, so I'm interested to see what's being changed.
Long War type elements would be great, even if you have to opt into them like the second wave stuff. It would be pretty cool if the story has you taking the fight to the aliens home planet for some of it, just different maps and terrain, maybe some atmospheric stuff you have to account for with loadouts (toxicity etc)