First of all, having the weapon damage for laser weaponry be visually reflected by the intensity of the beam you shoot, so a laser rifle looks brighter than a laser pistol. Perhaps different coloured beams by customisation or by damage thresholds. Red for lower damage, blue for higher damage. And as an extra bit of flavour, you could have them produce a weak, undamaging beam when you try to shoot with the battery drained.
Speaking of batteries, they should only be picked up as singular objects that have a varying amount of shots depending on which weapon you stick it in. So you come across 1 microfusion cell in a ammo crate, and that one cell can be loaded into a laser rifle for 24 shots before running dry, but if it gets loaded into gatling laser (assuming they'll also use MFCs as ammo) it would give you 240 shots. And if you use 4 shots from the laser rifle, if you use the same cell for the gatling laser, you'll be down to 200 for that gun, not 236. Fallout New Vegas attempted this with different EW using up different numbers of energy cells but it wasn't conveyed very well and the batteries were still effectively just bullets of a different stripe.
Last but most importantly for the OCD-addled people like myself, make sure ash piles clean up like regular corpses! We don't need save file bloat.
I'm hoping the new modification system will help make energy weapons seem less like ballistic weaponry and more like their own thing, but that's something we'll have to wait for until November. I do wish for there to be both homemade/"low-tech" energy weapons (like that wind-up laser gun straight from Futurama) and the Fallout 3 style hi-tech fancy stuff like we saw in the modification demo. Fallout 3's energy weaponry was a bit lacking, and I personally disliked the look of the new ones in New Vegas. Just what was the LAER about?