I have to say that S5 is my least favourite AtS season. As a loyal Angel viewer I kinda felt betrayed when they tried to bent Angel into BtVS light to attract the Buffy viewers. I loved the story arc, the darkness, the premises of the show and didn't take it well when they tried to make 180 degree turn.
We loose 3 of my favourite characters, Cordelia, Connor and Lilah and they are substituted through very weak ones ... Spike, Harmony and Eve. S4 still had atmosphere in spades, S5 lacked any real Angel feeling for most of the season. While the W&H sets were neat, they couldn't replace the fantastic film-noir settings of the Hyperion. Angel running around in suits and bright daylight didn't fit either. Also I'd rather have AI fighting with each other because they are close friends, able to hurt each other because of that closeness, than have them distanced in different bureaus, acting as if they are only casual acquaintances.
Some other problems for me are: Lindseys return .. completely wasted. The ruined his whole character development from S2 for a simple surprise effect. I hated his arc and for me they destroyed a great character there. S5 also denied Cordelia and Connor a full redemption story in the eyes of the viewer after they were shamelessly misused and violated in S4. The show never felt the same again when Cordy was gone.
But mainly my complaint goes into the direction of losing the premise of the show when they moved on to W&H. I get the *Can we keep our ideals when we make that deal* metaphor clearly and loud, but the answer already was clear from the beginning. To me Angel was always about redemption and the saving of souls:
"žIt's about reaching out to people, showing them that there's love and hope still left in the world. It's not about saving lives; it's about saving souls. Hey, possibly your own in the process." (Doyle, City of ...)
"žWe're not running a race - we're doing a job - one soul at a time" (Wesley, Judgment)
"žThere's no grand plan, no big win. If there is no great glorious end to all this, if - nothing we do matters, - then all that matters is what we do. 'cause that's all there is. What we do, now, today. All I wanna do is help. I wanna help because - I don't think people should suffer, as they do. Because, if there is no bigger meaning, then the smallest act of kindness - is the greatest thing in the world." (Angel, Epiphany)
Moving in to W&H and start making deals with demon clans and only working towards the infamous *bigger picture* somehow diminishes what they achieved in the early years. It's not that I didn't enjoy a lot of S5 but it only started to feel like AtS in the last couple of episodes.
What I liked best about that season is the closure it brought to a lot of loose ends of the show. You're Welcome and Origin are among my favourite episodes ever. I also liked the *Angel loosing his faith in his destiny* plotline and the final strike at the SP. Not Fade Away has to be among the best series finals ever.