1) Only 5 companions. That means you need to take them all with you if you have a 6 person party. Worked in PS:T but that was a RPG unlike any other.
I'm a bit indifferent on your other concerns (Either because I already agree with you or I think there isn't enough info to be concerned), but this is a really good point. They didn't mention party size, so either it'll be small (Something like the Bioware-standard PC and two companions at once) or like you said you'll be taking everyone/most everyone with you. When I heard isometric party RPG I figured it was going to be a relatively large party, but 5 companions gives me second thoughts.
Probably not enough to get me to pull my money like you, but that is kind of a letdown.
Actually, fuck. I just looked at their Kickstarter page again and they don't even mention isometric, not sure how I was adding that. They just say real time with pause and party. IT'S GOING TO BE DRAGON AGE 2. EVERY PARTY MEMBER WILL BE FUCKABLE FOR ALL GENDERS. ABANDON SHIP, ABANDON SHIP!