I'm not usually one for drastic suggestions on here (well maybe once or twice) but I was watching the Gyle cast this week and had the thought that maybe a mobile missile rework could be in order:
Add a mobile TMD.
Split mobile missile launchers in to two groups or have two settings on them, one for normal operation (best vs buildings) and another higher rate of fire, lower damage, and partial unit locking setting (making them much more usable vs spam units.
Not perfect locking just somewhat better (IE splash hits on units moving in straight lines but missing jukers)
anyone else have thoughts?