The weakest main character from Angel was Angel. His arc had concluded in Buffy the Vampire Slayer and the corpse of that arc is what we got for a primary protagonist character in the spinoff. Gunn might have been poorly written on all fronts considering ethnicity and poverty level (in cinematic history? Watch any other show from the time period. Yeah it was bad, but in cinematic history? Hyperbole much?), but at least he had interesting character interactions and story arcs when you look past that. Angel on the other hand... eughhh... stiff as a board and the most boring arcs of any of the characters on the show. Same story again and again, and the only time he's ever actually interesting is (gasp, just like on Buffy) when he's Angelus. Maybe that's an unpopular opinion, and I hate calling anything that, but it's pretty much how I feel.

Still, the show itself is undeniably great, with Cordelia's earlier seasons and Wesley's growth being perhaps the most excellent of any in either Whedon show, and the undeniably great final season. It's lucky that the supporting cast was so very good and written so well on many levels.