You see, there's a fatal flaw to this programme, one which could potentially have been avoided - it doesn't actually matter who the mother is. The whole point of the show is that eventually, Ted will meet his wife and the mother of the kids he's telling the story to. Except, does it really matter who she is? At this point, deep into season 8, we already know pretty much everything about her. In fact, we know basically everything except for her name and what she looks like. And that is it. We even know exactly when and where Ted meets her, so all the mystery is just gone. Honestly, when they reveal the mother, the only thing they'll actually be revealing is which actress they cast to play her. It doesn't matter who she is.
Unless they cheat. The programme makers have stated categorically that the mother is not someone we've met on the show before. If it was someone we'd met, or if that option was still open, then that tension and mystery would still be there - Ted meets her at Barney and Robin's wedding, could it really be Robin somehow? Does Victoria come back again? Is it Zoe or Stella or Bump Girl? All of these would bother me, (except for Bump Girl, who you can find out more about here) because then we've been lied to. And I would feel like the writers painted themselves into a corner and struggled to get out again. And that's cheating and unacceptable.
So it can't be someone we've already met before, meaning ultimately, it doesn't really matter who the mother is. The show has gone on so long and every avenue explored so many times over and so many details revealed that all the mystery has gone. I still watch the show, I still enjoy it and get excited whenever new hints about the mother are dropped, but it's usually followed by disappointment. And I worry that the end of this series will be the biggest anti-climax of recent television history. (I feel compelled to add that I never made it past season 2 of Lost.)