I loved the first three seasons, despite all the griping I kept hearing about Season 3's shortcomings. Sure, it had some problems, but the story arc kept me interested right up until the season finale. Season 4 has been a *huge* disappointment to me thus far, though, and I think it's down to what others have been saying: the lack of a unifying story arc. They just kind of blew off all the loose threads from last year and have now reverted to a lame "mission-of-the-week" format.
Also, is it just me, or do all the characters seem somewhat "off" this season? That is is to say, their interactions all seem more forced than usual, almost as if the actors and the writing just aren't meshing quite right. Or maybe it's just that I'm sick to death of the whole Sydney-Vaughn relationship angle.
Ok, enough ranting from me. I'll keep watching in the hope that the show will find its footing and get back to the quality of its former incarnations, but I'm not terribly optimistic at this point...