In real life, semi-active radar guided missiles often require continuous input from the launching unit in order to guide it accurately to the target.
Currently, the missile can be fired and then the lock immediately removed, etc. This encourages spamming missiles & other bad behaviors.
Instead, the lock tone should be maintained throughout the missile's flight time, requiring more focus from the firing unit.
A player should not be able to have two radar guided missiles in flight and have them both track individual targets.

It would make firing Titan MPRL and Air to Air radar guided missiles a much less thoughtless click-to-win process. In exchange for this requirement, said missiles would have a slightly higher kill probability, as well as a reduced chance of being spoofed by flares (they shouldn't be period, but that's a different issue).