The ending was okay and it worked with how the show went. Though they could have matched the lighting better between the scenes that were taped of the kids years ago and the new footage of Ted at the end.

But this is the ending I wanted.
He is talking to the kids, They show him talking back and forth but it just shows the back of his head. He says "...and that is how I met your mother." As the camera zooms out and you see him talking to a white wall. And he is in this padded white room Then the camera zooms out some more and there are two doctors there an older one and a younger one. The younger says "what is his story?"
Then the old one says " it is sad, he was a successful architect. Then his Pregnant wife daughter, and four bests friends died in a car crash on their way to an opening of his new building."

Then just leave it at that.