If the fluff is your primary objection to the models, the other (faster, better, and cheaper) alternative is simply writing new fluff for your drop army
I agree that it's incredibly lame fluff for the Elysians, and not representative of what the army's weapon testing has found about effective rates of fire. However, because the game mechanics don't differentiate between short burst fire or single aimed shots, because it's easier to change the fluff than the kits, and because the Elysian lasguns look pretty cool, I'd personally rewrite before I resculpted.
Also, the "conserve ammo" thing sounds like a big load to me. Other fluff describes how lasgun clips recharge in sunlight or in a campfire. Unless they're in a constant firefight, Guardsmen don't need a resupply to get fresh magazines.