Im also sort of disappointed that they didnt make him more of a part of the Fallout 3 story, but its no big deal. If anything I appreciate it for the fact it acknowledges a previous protagonist from a fallout game, like 4 never brings up the slightest bit of reference to the Lone Wanderer and it makes me sad. I just discovered the guy today and was absolutely surprised that I havent heard more around the net about this awesome character. That's the first time we've ever actually heard of anything alluding to a fallout protagonist being a set character with a gender and name, all other games keep it ambiguous as to if they were male of female as well as good or evil. Also, if you question him about the name of the town he says its named after 'an old friend' and that he 'doesn't know what ever happened to him, but hopes things turned out well' (I'm paraphrasing, haven't played new Vegas in like 3 years) but this is an obvious reference to The Chosen One who may be dead now seeing as NV takes place 40 years after 2. Hes the mayor of Jacob's town, illustrating he built a safe haven for his kind and that they aren't entirely mindless monsters.
Not so much the character in a whole but only because I haven't played Fallout 2 personally, but Marcus' appearance in Fallout New Vegas.