I think alot more people are fans of the original toyline first and foremost than any of the cartoons. The line will have been seen as a success if the original toyline's figure roster was completed--this was a mentality that came from the 200X days. Fans wanted to see the old roster of toys reimagined with the 4H's redesigns, but 200X/MYP died before that could happen. Now for Classics, fans want to see the entire roster of characters in 6" scale before time is up.
I do see and understand where you are coming from. Some characters DO get a pass because they were in the vintage line, not because they were awesome characters. It's a shame that characters who actually have shown up in media are upstaged by characters who weren't for the sake of completion.