Automated control groups: I think control groups in general could use some work. Be it automated army control group generation, or also automating elements like control group subdivision for armies and production based on unit/structure hierarchy. Control groups are needlessly difficult and hard to manage in SCII. They sort of started it with the select army button, but being able to have automatic control group generation and control group subdivision would help out a lot. How you want the control groups generated could be managed through settings.You could also have an easy way to split units off from automatically being a part of the main army control groups or whatnot, for drops and things like that.
Revamped Training: Training not only gives you challenges that help you learn how to control the units etc, but actually prepares you for how multiplayer is actually played
Improved select-able 'AI Strategies': Their techniques will actually allow them to replicate the openings of strategies used in real competitive play and are frequently updated.
Unit/building construction progress on control group icons We have a graphical indicator for the hotkeyed warp gates to show when they are ready again, why don't we also see a construction bar for all production?