Why not just learn to manage your saves better? Really? If I saved at point A, kept playing, and saved at point B then as long as I'm satisfied with my progress there is absolutely no need to keep save A. For 10 characters, 20 saves is too much IMO. For 2 or three having 100+ saves? Come on, I seriously doubt you need all of those.
The problem is that Oblivion, FO3, and New Vegas were all fairly buggy. Let's say, a little after point A, you got a specific perk. Then, at about point C, you realize that perk causes some game-breaking bug* that can only be avoided by NOT taking that perk. Or maybe messed up faction settings cause some hostile turrets and robots to technically be allied with another character who is in no way actually involved with anything about even just the area the enemies are in**, immediately making his forces hostile to you when you defend yourself and locking yourself out of one of the endings. Or maybe you're running on the PC version and whoops, some scripted effect from a mod just backfired VERY badly and now you can't do a thing at all***. Now, what's the better option here, starting the game over, or starting at point A, which despite the name, may still be VERY far into the game
*The bad game-crashing kind of game-breaking, not the good "whoa look at all these enemies catapulting into the air" game-breaking
**Actual (Fixed) New Vegas bug
***Based off of actual modded Oblivion experiences