I like the newer games for what they are, but like @wimpiam said above, I don't really consider them RPGs. The original fallout emulates tabletop play while the newer games are more adventure games with some light RPG elements.

In tabletop games like Dungeons and Dragons, players rarely ever have more that 2 or 3 quests going on. For instance, in the campaign I'm running, the party has an overarching quest to defeat the ultimate bad guy, but as they journey, they may run into much smaller quests that take 1 or 2 sessions of play to get through that may not be linked to the main story arc, but move the players forward. It's impossible in a tabletop game to run to every npc and get every quest in that region and complete them. The smaller quests are contained stories to be completed all the way through without derailing onto to something else.

It's easier in a tabletop sense to have that kind of focus as a there is a person playing the game master. I think Fallout, the first two, are attempting to do that. It's often up to the players to keep track of what they are doing in a tabletop game. For instance, my players have journals where they write notes of the adventure so far and can recall facts or points that may have come up or things NPCs said.

It's just a more rough around the edges vibe that I think gave the original RPG games that appeal.

But like I said, I like the new games for what they are. I probably have 300 hours in fallout 3 and 500 hours in skyrim myself! Haha.