In a nutshell, the two don't even compare - hardcoe in NV seems like a joke in comparison. It has huge potential, but once again, as with FO3, it's going to be up to the modders to make NV realize that potential. And frankly, I'm probably going to be waiting quite a while for some really good NV mods to come out, as well as a couple more NV patches to fix stability issues, before I start playing it again.
So I'll still be using good Fallout 3 mods for some time to come.
I couldn't agree more - after 258 hours in New Vegas and then several weeks without playing, I see the games as very equal overall (different/better in various respects). I was also initially worried about the same thing where people would loose interest in any mod made for Fallout 3 now and with New Vegas out.
What I find refreshing is that the Fallout 3 modding community is still quite active compared to New Vegas, which as you aptly pointed out is still on the up-curve of modding activity. I say that because I noted that my Fo3Edit manual is still getting more downloads than my FNV-Edit manual, which tells me that there are alot more modders out there who are actively working on Fallout 3 mods (and who need help from Fo3Edit/FNVEdit). Like the sale of men's underwear is often a strong bell weather of how the economy is doing, I figure that the level of Fo3Edit/FNVEdit downloads is also as a sort of "activity barometer" of where lots of modding is still taking place. If Fo3 modding was falling off, I would see very few Fo3Edit/tutorial downloads versus FNVEdit/tutorial downloads, but the reverse is true.
Overall I have more confidence now that my fears of New Vegas making Fallout 3 mods useless was unfounded, and that there is still plenty of Fallout 3 modders out there still working on projects right along with us.