I think theres a diffrence though bc Osborn and Bucky are 2 significant characters no matter how long they were dead. Thunderbird? Not so much. He only has history with 2 characters, his brother and Xavier. Frankly theres not even much there with Xavier as he will be just another X-man who's come back from the dead and Xavier has dealt with others which he was more emotinoally connected to like Jean, Collossus, etc... Thunderbird is a total D lister who adds nothing. Not much story potential to come out of them keeping him around, whereas there was with Osborn and Bucky