There is exactly one way to successfully play this game:
Ultra defensive, advancing ultra slow
Nope.
Most of your criticism can just be deflected with a single "l2p" comment, except for the missions where you start spread out, cuz those really can be a lethal coin toss, particularly the ones where teams are scattered randomly around an area - the ones where you start split into 3 groups are easy to manage in terms of survival. Still, taking them every now and again serves as a fun enough change in variety if you can handle the risk.
The game is largely the same as Blood Bowl. At first it seems completely unforgiving and frustrating, but then you learn the ropes better and start properly managing the risk, which leads to having fun and knowing what you're doing. I remember I had to scrap my first Skaven warband after entering a downward spiral of losing initially because I had little idea of how everything worked. But then on 2nd try I was much more successful. Perhaps it didn't bother me that much, because that was exactly how I started in BB too. It was even a Skaven team in BB as well.