Barney is a great example of how bad that finale just killed the show for certain characters. Rather then just be okay with the development they had..... they over the course of years that took place in that episode undid all of it and brought him bank to where he was.... only to have him go through it all again so he can end exactly where they already had him only now his final development that mattered was rushed and unearned because they wiped away what years of the show gave us.
It’s like they had a perfectly fine set up for a good finale and then blew it to go too big. And when you have a show that runs for years you really don’t want to see a bunch of development and major plot points forced into the last episode when you just had a long running show where you could have just done that if it was your end game.