Simple idea: Introduce more defensive benefits into the 'secondary' combat profs to allow them to be combined more favourably in more templates.
The big ones:
BH - I'm not particularly well versed in BH mechanics, but Pistol BH can take advantage of Dodge. Carbine BH can take advantage of Counterattack. Why not give LLC BH the ability to block. (I assume that they do not.) - Secondarily for BH, would they benefit from changing their mitigation to melee mit. to give them more synergy with the other ranged profs? I've not noticed many complaints by BH about mitigation, but it would perhaps allow BH to be part of more varied PvE temps.
Commando - Commando is odd in that it has zero methods of defense outside of it's ranged damage mitigation. Why not allow heavy weapons to use a defensive capability such as Block/Counterattack/Dodge, similarly to what I suggest goes to the LLC. I would also contend that commando would be vastly improved by changing it's mitigation to melee mitigation, allowing it to synergize more readily with ranged profs, as suggested for BH.
Creature Handler and Ranger - CH is woefully inadequate in the defensive department. CH pets can very roughly be considered to tank if you have them attack a lair and draw occasional npc attention. I suggest granting CH state defenses as well as smuggler-style mixed mitigation, to make CH less punishing to use. - The Same could be done with Ranger, making it less of a dead weight in combat groups.
Less importantly:
Medic, Doctor and CM.
With zero defenses of any kind, these can be included in a variety of templates, but their inclusion does not always prove useful. There's a reason we see primarily only Rifle/CM characters. With the introduction of some lower-tier state, melee+ranged defenses and split 'smuggler style' mitigation, Med, Doc and CM could become much more significant linchpins in new builds.
Conceptually these ideas reduce the importance of defense stacking, and break the status quo of many ironclad builds. Indeed, the CM suggestion would make the CM rifleman even stronger, but that could be significantly offset by firing back as a doctor or commando with fewer 'penalties' for inclusion in their temps. I don't believe any of these suggestions are true fixes in their own right, but illustrate some options that the devs could use to emphasize the customizability of SWG, one of it's strongest factors.

.png)