Fallouts 1 and 2 are ok although they aren't as good as Fallout 3 and New Vegas. The 10 year difference in technology is the main reason.
Technology didnt help too much the games nowadays thougth :rolleyes:
Gamebryo is buggy, very buggy, I dont remember the older games being so problematic in that terms, not even the unpatched Fallout 2 was so ridiculously messy, and the game was rushed
Other examples. well, look at DA2 and Fable 3
Also, the plot was better in FO1 and FO2 then FO3 and New Vegas