Thanks for playing and leaving such in-depth feedback. :)
You make some good points about the ability controls, which yeah, they've been an issue from the start. This is an old issue I should revisit now.
Gamepad controls are one barrier here. Spacebar sounds great for desktop, but the best thing I can think of on gamepad is right bumper, which isn't great.
The second problem is that the sniper actually takes your shield down completely while it's activated. It would be too powerful otherwise. The assumption there is that you only have the sniper activated while sniping.
I'll see if I can come up with anything. On the bright side, the ability ordering actually works exactly how you described, or at least it should work that way. If you buy the shotgun and map it to 1, it should stay mapped to 1 throughout the match. :)
Thanks again man!