there will most likely be factions, i am willing to bet on it in fact. and i suggest you do give 3/nv a try, the graphics are pretty damn good imo
We don't know yet. FO4 was announced literally this month, and the only information we have from it is from a small smattering of leaks and the E3 demos.
Son, if gaming is reliant on graphics for you - then you're missing out on a lot.
Get over eye blink and simply explore something new and you might be surprised what you end up liking.
Unlike TES where you can join a variety of schools/guilds, Fallout hasn't followed that theme too much.
You're mostly a (wo)man on a mission exploring away and following your own personal moral compass. You may - temporarily - align with certain groups in the wasteland, but generally not for good.
If you can get the games on PC, there are plenty of mods that can make the graphics pretty impressive. I wholeheartedly recommend you try and play those games, they're all excellent in their own ways.
Anyway, there aren't really "guilds" in the Fallout universe. There are different factions, and they vary a lot based on the region, but generally they're designed around politics and ideologies rather than how Elder Scrolls has factions for different character types. For instance there are slaver factions, or drug gangs, or even new governments trying to expand their territory.