I submitted a much shorter review but after reading a few comments I felt compelled to contribute a bit more.
Two factors keep cropping up time and again with these reviews the first is people complaining that the now revealed "Mother" is not Robin, large numbers of people claiming to be long standing fans of the show saying they expected it to be Robin, several problems here firstly Robin has revealed that she CAN'T have kids nor does she want them ergo she can't be the mother, secondly the narrator has repeatedly referred to her as "aunt" Robin and finally (if you've not been watching) she's been engaged to Barney for a while now and season 9 will start with their wedding all of which points to her definitely NOT being the mother.
My second problem is people complaining about the actress playing "the mother" as being "plain" or "not famous enough", well I'm sorry but if you can't get over the fact that ... (insert overly referenced female actress here)... isn't in the role you want her to be in then frankly you shouldn't be watching a TV show that wasn't created by you, her lack of history is actually an advantage because she can come in and create a character without us comparing her to other roles, "the mother" needs to be a fresh face because she can't afford to be overshadowed by past performances.
My other gripe here is that the woman cast as "the mother" IS pretty she's NOT plain, she's just pretty in a cute sort of way rather than being an absolute stunner and that fits the shows feel vastly more than if they'd cast someone overbearingly beautiful, she's a cute brunette, she's got damn fine legs, wears boots (very sexy), lovely eyes, I honestly don't see what people are complaining about.
For the future, I really want season 9 to show some of the relationship develop between Ted and "the mother", I know the show's called "How I met your mother" so if they just show us the introduction it will technically be fulfilling it's commitment but I would personally feel a little short changed if I the meeting and nothing beyond that.