Angel never reached the quality of Buffy as its zenith. But Whedon's Buffy and Marti Noxon's Buffy are entirely different shows, and people tend to like one over the other. And Angel basically changed formats every season.
Season One was Moonlighting
with vampires, followed by Xena
in Season Two, a revenge story, a (ugh!!) prime time soap, a Body Snatchers
paranoia story, and finally David E. Kelly with vampires. (Full circle?) The one common thread is Evilcorp itself, the law firm of Wolfram & Hart (a parody of Jacoby & Meyers). I always find myself rooting for the bad guys, both because their development is in tandem with the heroes, and that they're just trying to make it through the day without getting axed, literally.
I say this with affection, but Angel is a genre show with pretensions, which is not always good. A lot of Season Four is pure filler, people talking in shot-reverse-shot about crap we already know (thanks to ever-lengthy Previously Ons
) and shipping characters all over the place. In Season Five, the pathos is unrelenting and a bit over-the-top, like in Buffy's later years. Supernatural, and Doctor Who, and others tend toward the angsty, juggling fun and drama, and sometimes the juxtaposition feels inconsistent. BUT, the advantage of the repetitive format is that you can jump into the show anytime, enhancing its longevity. Angel is too inconsistent to be a classic. As I said, it's a genre show — and a pretty good one: the standalone episodes are fun, and the plot arcs have lasting consequences.
The upside is that the characters feel like real people, with complex relationships with each other. By Season Five, you feel like you've lived a lifetime with these people; some of them look the worse for wear. I guess you can call it character development, but it's a bit more than that. Some, like Wesley and Cordelia — and Angel, obviously — have had time to develop between two
shows, sometimes maxing out at seven years. The Buffyverse is not a self-contained story; it's more like a family home video on fast forward, with a few relatives dying off, and others going to the bottle, and your aunt being impregnated by an evil fallen God. It's pretty heartbreaking to see them grow and change, for the good and the bad. You can't really say that for most shows.