I like most of your ideas Leo. I often think about rolling an Emp, as I used to truly enjoy playing them, but then I think to myself, "Why?".
I think in addition to some or all of the changes you suggest, how about an option to raise the difficulty level beyond +4? To +6 or even +8, but with, and this is important, with NO additional XP or INF reward past what +4 already offers, to add some additional difficulty for those who desire it, just for the love of the challenge. The game, while still more fun than a barrel of monkeys, has gotten too easy. Team composition no longer matters much. Every now and then I run into "We need a...", but it is very rare.