Well, I'll eat my crow about the mother dying, but I'll take some solace in the fact that it's only because this show is actually dumb enough to end it that way.
Things that ground my gears:
-Barney ultimately grows none as a person by the end of the series, and when you look at it from far away, he was basically just used in the last few seasons to deprive Ted of Robin for a little while. They take back every episode reaffirming Barney having changed, being capable of love, and that Robin actually has way more in common with Barney so they belong together.
-The show then makes their wedding the centerpiece of an entire season, reaffirms several times that Robin and Barney are TOTALLY the perfect couple, marries them ON THE SECOND-TO-LAST EPISODE, then divorces them the NEXT episode in a really lazy way. Even if you were rooting for Ted and Robin, you probably still feel pretty cheated getting there. Just so many pointless episodes...
-I guess it's common for finales, but there were a few too many of the inside jokes and callbacks to old episodes when I would have rather they spend time creating a better story for finishing the series.
-How is Ted going to be any better off with Robin's international lifestyle than Barney was? Based on their jobs, Barney should have been way more adaptive to moving around. Not to mention Ted's kids. Did I miss something about Robin settling down in NY?
Things I Liked:
-Since they destroyed Barney's character, I like that he at least had a happy ending by being--by all accounts-- a devoted dad. Unfortunately this will probably be negated in the HIMYM reunion show where they will turn him into an abusive dad or maybe just kill him off, either way ironically passing on daddy issues to his own daughter.
-Ted's daughter is hawt
-I enjoyed the continued scenes with the mother. They had a good moment with the train station, and any other scene with her just made you like her more, especially for Ted. Unfortunately that's what makes it so disappointing that they created such a good match, yet they make it about Robin in the end.
Overall, I mostly enjoyed the finale aside from the divorce and mother dying/getting back with Robin. It definitely had some moments, and I'm not going to put it in the same category as Dexter, but that's mainly because Dexter's finale is in a category all its own.