Actually, SAO's series premise is absolutely fine, IMO. In fact, the setting/premise are just about the only redeeming qualities.
It's just the way the author goes about it - the novels themselves start with, and are focused more on the AsunaxKirito MarySuexGaryStu (the author has admitted this in an interview) romance (that you really don't care about) more than the level-clearing/rpg dynamics/life-death game/whatnot (what you actually want to read) that the premise suggests. The anime shows events chronologically, while in the novels, the content of the first few episodes with the random-girl-of-the-week are revealed in various flashback sequences.
The second part (ALO) just compounds on everything that was bad in the first part, completely discarding the guise of the "interesting" premise/setting and plunging straight into the dumb. Though I do hear that the later parts - GGO etc. - (which the anime doesn't get to) get better (?).
I will say that I did enjoy the series.
Well, laughing at it was fairly enjoyable.