Also, as Kyoss pointed out: It may not be a good choice to provide the best anti-shield weapon (EM) with a mod to deal the best anti-hull weapon damage (kinetic). Perhaps both plasma and rail should get thermal damage mods? I would however suggest that laser does not get damage type mods at all, since thermal is medium-effective to both types, and the instant no-leading projectiles is a significant benefit already.
Thermal damage is a strange one. It has the best weapon for long range (no projectile) it has decent damage both on shield and hull, it can change to em.
But; guided missiles, desintegrator, pulsar module and the high damage explosives (cruise, octopus, firestorm, tactical nuke, death-ray, mine field,proximity mine) are thermal damage too.
At the moment the best resist to have is thermal. If you take out damage type mod for laser their damage would be nerfed hard.
If you take out every damage type mod, that would be a disaster (try to kill an empire ship with em, or a jericho with a rail… Not. Gonna. Happen.)
The suggestion (plasma: em/thermal, rail:kin/thermal, laser: only thermal compensating that it don’t have projectile speed problems) would be great if they change the main damage dealer skills/missile weapons damage type (at least evenly to em/kin/thermal).