But some weapons would be lore-breaking to have back though.
IIRC Heavy Incinerator was a new design. Bio-gas canisters were only a prototype which had a set amount in PL, Tesla Cannon was developed with the help of The Lone Wanderer.
None of these would make any sense to have in Vegas.
I mean, how would they even get there?
(Might seem like I'm a hypocrite but we all know that aliens don't have a set area, there could be a crashed UFO with alien weapons from MZ in it. They're all around the world.)
So it has to make sense, lore-wise.
Well the Lone Wanderer and Harold obviously brought them over on all the stolen Enclave Vertibirds. Duh. =P[/sarcasm]
Nah, I don't expect any of the weapons from FO3 besides a few (like the DKS-501 Sniper Rifle) to make an appearance in New Vegas, but those are just weapons or similar weapons I wouldn't mind having in New Vegas. I don't really even care for the Auto Axe, I just would like a big chainsaw-like weapon because I hated the Ripper. It felt overpowered for it's weight to me, and I'd much rather tear apart limbs with http://images3.wikia.nocookie.net/left4dead/images/4/40/Render-chainsaw.jpg
The Heavy Incinerator I wouldn't expect, but I would love another napalm launching weapon. I wasn't really big on the Flamer, but once I got the HI, I loved finding flamer fuel.
Bio-Gas Canisters I could see though. Yes they were prototypes, but who's to say they didn't release them out to some other research facilities? There weren't many of the canisters in Point Lookout as it was, so it could be the same in New Vegas. A fun toy to use for a little while, but limited in supply.