Well i don't know, the show and books deals with symbolism a lot of times so i don't know.

They show runners are really struggling with how to put the characters in the plots they need to be without being contrived, but I guess they are really getting tired with this show and they just want to finish it.

That's kinda sad because the only developed dragon is Drogon and that's because it has a connection with Dany. But Viserion and Rhaegal has no personality beyond not being Drogon. But well, I guess you can throw away "the dragon has three heads" phrase.