I personally would like to see weapon integration, at least as an optional feature. Even for DLCs, for example [url=http://www.nexusmods.com/newvegas/mods/47880/?]this[/url] mod and [url=http://www.nexusmods.com/newvegas/mods/46251/?]this[/url] other mod provide a good working base for dlc weapons of new vegas.
In addition to this I think it would be good to integrate the weapons of the other DLCs, the fallout 3 ones, so they are available in both wastelands. Overall this increases the diversity of the enemies encountered.
Also how possible would it be for the gun runner arsenal weapons to substitute the originals? I.e. just delete the original duplicate weapon and take out the (GRA) part of the name of the new ones? Whenever I play I think it just adds a level of granularity that I don't enjoy. I don't know how popular this opinion is.