While I am somewhat sympathetic to some of your gripes, some of these game "complaints" (yours in this post, but more so from others in general) are really just complaints about the type of online experience that is common to all games - unless you play with like-minded players.
Go play COD3 or Halo2 with a bunch of people you don't know and see how long it takes to find a game full of team-killing foul-mouthed idiots. Or try Gears or Rainbow 6 or GRAW2 or Battlestations : Midway or just about any other online-enabled game. Sports games are notoriously the worst (well maybe tied with FPS games).
The problem is that if you actually care about your online rank or what your meaningless W/L record says, then you must either play with these fools (and most of their unrealistic crap is easily beaten; although boring as hell, and usually results in them quitting after their pet plays are locked down or repeatedly torched) or choose not to play the game at all.
So, yes, if rank and win % are important to you as a measure of self-esteem or actual measure of "skill", then by all means avoid the game online. However, if you choose to ignore those things (either by playing through it or simply quitting the game when you find you are matched against a clown) or just find like-minded players online, then NCAA 2008 is a vastly better game than 2007.
I would disagree on a "C-" grade for many reasons - Campus Legend and Dynasty Modes offline are actually quite fun. So are the mini-games for that matter. The CPU gameplay is no where near as annoying as the random online idiots and the online play (with the right people and a solid connection) is top notch.
I don't know if I could give it an "A", but a solid "B+" is in order IMO that is...