-No, AC respecs would destory the game more.
If Tracer had a CD. It would allow you to keep your heat low because youd be forced to fill that 1.5 secs with rapid fire or possibly MB/ER
that 1.5s would be filled with the GCD. there is no reason to give it any cooldown, just make it instant in that case.
however, have fun fighitng with people over why that is a) a good and easy fix and b) why it is not overpowered