Are you also mixing weapons from the 2 wastelands?
Because i think it would be cool to leave them separated as most as possible... it actually add more atmosphere about being 2 different places... i really wouldn't like to found western weapons of fallout new vegas on DC... it really didn't make that much sense... i think it would be ok just to add compatibility between them (so you can repair DC weapons with New vegas weapons and viceversa...). What do you think?
This way DC would be a really new area with his typical weapons and stuff... I don't think it would really make sense to see fuse dynamites on Washington DC... :/ Indeed there are Plasma granades/mines on DC...
Moreover apart from being better (at least in my opinion) it would also leave you A LOT of free time with other stuffs, and will let you focus on fixes and more important problems...
Obviously the same is for Armors and other items... It really don't make sense seeing sarsaparillas on DC... XD
On DC you would instead search for Quantum cola... :)