The chance of hitting a stationary 12m target is roughly 52%, regardless of the tracking on the weapon. Things only get worse if the target is moving, which is what tracking mitigates.
Target painters circumvent misses due to size, so yeah, they’re important to keep frigate AA missiles optimal.
“Overspending” is fine, provided you find ways to turn your AA solutions into other useful defenses or offenses. Painters can be used against everything. Frigate AA missiles do semidecent damage vs unprotected targets. Armor has uses as well. Tractors and CDL’s… not so much.
That’s not to say tractors aren’t useful, you just have to be careful with them because they generally don’t give any return besides antifighter applications.
Fighter defense is part offense and part defense. Have impenetrable armor (or shields, if they’re rocket fighters) and fighters don’t matter. Kill them fast enough and you won’t need nearly as much defense.
If you’re going for the latter route, consider frigates. They’re really the premier antiaircraft platform as far as sheer volume goes - they get both the 12.5 tracking missiles and a tractor beam that costs near a third of the cruiser variants. They are easy to armor and their small bubbles make them a completely unreasonable target for laser fighters.
This is offset by the increased risk of assassination by other craft, which is the real difference between a coherent fighter rush and mere fighter spam.