The cybran T1 aa is the only one with tracking missiles. this is a double edged however. T1 bommbers will almost always make a single pass against them and mercys. The only way to protect your acu from mercys as cybran in t1 are
T1 aa turret.
interceptors.
The aa turret is expensive and takes time to build and you have to stand in the center of it as mercys have great range + you might need more than one to stop all mercys.
The interceptors can be killed by the aeon t2 swift wind with ease.
T2 gunships. They own all t1 aa but cybran the most as it has by far the least hp.
I have kiled a cybran comm with mercys who was reasonably aa protected and if those aa were any other t1 one my snipe would have compley failed. infact i would not have even considered doing it. Send a t1 scout/ intie first and its almost a gauranteed kill
on the upside you can ocasonaly hit T3 air and it dont miss agsinst t2 air or under.
So you could make the missiles faster acceleration or top speed prehaps or make it have more health or all 3?
another note - overkill. you get about 200 missiles a one bommber and the rest drop there bombs