The assault rifle should be renamed to "LMG", and should be upgradeable to .308, at which point it is renamed to "MMG". Aesthetically, it should remain the same; it's a Power Armor weapon, and the liquid-cooled function fits that. Functionally, it should only be fully automatic.
The combat rifle should be chambered in 5.56 initially, and the option should remain to upgrade it to .308, at which point it should be renamed "Battle Rifle". Single-shot, burst-fire and full auto receivers should be available.
The 10mm pistol should have an extended upgrade tree, including the option to add a stock and extended barrel. This would allow a fully-automatic alternative to the pipe SMG. The 10mm is a versatile weapon already; it would be nice to see it made even more useful.
The .38 rounds should be changed to 9mm; after all, they're practically the same round.
Pipe weapons should have an extended upgrade tree; after all, in your travels, you would probably find more intact, more modern bits and pieces to attach to your weapon. In effect, I'm just asking for collapsible stocks, polymer forearms (to replace the blocks of wood), rails, and upgraded sights. Even just the chance for clean shiny or black pipes would be cool.
When upgraded to fully stocked and barreled rifles, the hunting rifle/pistol should have the bolt moved to the right side. Rule of cool does rule, but it's weird to be working the bolt with your support hand.
A bit more pistol and shotgun variety would be cool as well, though I have no doubt that more weapons will be arriving in upcoming DLC.
Let me know what you guys think. Cheers!
-Joker243