Been a fan since the pilot. Have watched each episode of the first few seasons a few times thanks to reruns/Netflix, and have "hung in" during the ups and downs of the quality the last few seasons too.
A few thoughts:
1. First and foremost, I think to say that Ted still wanting Robin all these years later isn't exactly what they've been writing about for 9 years is to say that you haven't been paying attention. The whole "why are they beating the Ted/Robin horse" again is exactly that.
This is a pretty good overview of Ted/Robin
http://youtu.be/IJx7mERoZHg
2. The name of the show is "How I Met Your Mother", not "How I Dated Your Mother", "What life was like with your mother" or anything in that vein, so I think it isn't a big deal that they didn't spend a lot of time on them as a couple. That written, I do wonder if they had known how good the chemistry would be between the actors, if they might have spent more time on it. I mean, it would be pretty bad if he was telling this epic tale, and then once you saw them as a couple, it didn't look like they should be a couple.
3. Now usually, when you describe how you met your SO, you tell just the train station story, with some of the overlaps if you are dramatic (econ class, st. patty's day, dating the roommate, and I'd probably add the Barney/drugstore as that was the event that put them at the wedding) - but even if you ignore the fact they were trying to get seasons and seasons out of this, vs a miniseries, it makes sense that he would try to get the kids on board. Given their reaction in the pilot (not seeing her as someone he could be romantic with), he would have needed to make sure they "got it". The part that seems off for me is that they seemed so shocked back then, but now say its obvious that he has the hots for her.