The patch will fix some (but not all) important glitches and bugs I'm sure, what ones is anyone's guess. Despite everyone stating what it will and won't fix on these and other boards the perceptive ones among us will have noticed there is a distinct lack of a creditable source as to what it will 100% fix.
Basically whatever the first patch does there will be disappointment all round. Just look at the amount of negativity that has been spouted here already about this game (in my opinion one of the finest I've ever played), If you thought there were some lunatics already then wait and see what happens when the first patch doesn't completely change the UI or completely alter the leveling and perks system.
Why is it that some people have really bad problems and others don't? I'm on PS3 as well and my save file has reached 12 MB, aside from the occasional lagging, my game is fine.
Regarding this I would say a lot has to do with level of tolerance people have. For some a drop to 29 fps instead of a solid 30 will be enough for them cry shenanigans and start a campaign to never buy any Bethesda product again. Others will happily play on. I'm on ps3 and my save file is 13mb. In all honesty it probably became unplayable at the 10 -11mb mark for me but I carried on with shorter one or two dungeon sessions cos I'm weak and I need my skyrim hit. I'd guess your 12mb occasional lag file would have been given up on by many a player.
The ironic thing is that I went for the console option on launch as I thought it would be more stable. For the first 5-7 days after launch the ps3 version was probably the one with the least amount of complaints. I will eventually get it on PC when it everything gets ironed out and there are some good stable mods out there but i'm thinking that will be a while off yet.