I agree with prophecygrrl.
While I do think that the ending was a bit rushed, given the fact that they'd just been cancelled and needed to wrap everything up, I don't think there's anything bad I can say about the writing, or even that it differs to the earlier seasons. S5 had some great eps, in my opinion, including 'Origins', 'Not Fade Away', 'Destiny', 'Lineage', 'Shells' and 'Damaged'. I thought they were some of the best eps of the series.
As for Angel's quippage, I put that down to being around Spike again. Spike was like his annoying little brother, as, for those of you who have younger brothers or sisters, you know how hard it is to not get roped in when they start to tease you, and it turns into meaningless little squabbles. Now that they both had souls, and nothing else to turn their attentions to to get rid of the jealousy between them, they turned back into the school boys they were. It's been said time and again that Angel and Spike are immature, and nothing shows that more than when they're together. Which I found to be quite funny.
I don't think Angel was out of character this season. He's always had that dry, sarcastic sense of humor, and he came out with those one liners a lot. I don't think I can honestly say that S5 made Angel different to the other seasons. I just think that, now he had a solid, albeit evil, team behind him, he found time to relax.
---------- Post added at 02:06 AM ---------- Previous post was at 02:04 AM ----------
I think the house Angel entered uninvited was Lindsey and Eve's place when they went to search Lindsey's place for information.
The argument for that could be that it wasn't their house. If they killed the owners in order to find some place to live that was off the Senior Partners' radar, then it wasn't their house and therefore Angel was able to enter without an invite.
Or, the spells that Lindsey cast to keep the Senior Partners from finding them voided the need for an invite.