Nerfing buffers on T3s - cool idea.
Nerfing Ishtar DPS with sentries - not liking(I fly one:P) but I guess it's neccessary, those were OP.

Why not remove drone assist altogether though?
Solves *soooooo* many problems at once without touching much.

Nerfing rail DPS - oh come on... rails are good, but the tracking's rubbish, any transversal makes them very bad, and as such damage mitigation starts being a problem too. Leave rails alone, they were in a good spot before. Maybe do a 3-4% nerf if you think they *need* one.

BS/BC viability -
I'd just make BCs buffers 1.5x what they are now and BSes 2x and it'll be nicer from "how it should be IMO" perspective. Probably a bad move for balancing though so meh. You do what you want with them - won't be flying those much anyway:P