So here is my idea:
1. Remove the friendly laser (laser that sticks on a friendly vehicle), you cant lock onto it so no need to see it. This could also be done for CAS.
2. Change GTLD and other spotting tools to only see lasers that they are locked on. Idealy this would be your own laser, but anyway you will only see 1 laser at a time.
The only problem with this would be that the automated "i got lock" message needs to be removed to avoid spam. This could be replaced by another sound that is only triggered for CAS similar to how the AA lock on sound works. Also the rangefinder would only work when you have a target, but he is unreliable anyway (would probably be more accurate this way).
Additionally you could change the lock on time for GTLD to be non instant. This would force the spotter to keep his eyes on the target to see if the laser is still active. Popping up behind cover just to lase/check lase would be less effective.
At last there is a nice side effect from locking onto lasers: they are better visible.
Example:







