Re: First Class 3 or X-Men 5?
I kinda do, yea, lol.
But seriously though, for the most part, you're right. The main trilogy cast is the backbone of this film franchise for a number of reasons.
Patrick Stewart, Ian McKellen, Hugh Jackman, Halle Berry, Famke Jansen, Anna Paquin, Ellen Page > James McAvoy, Michael Fassbender, Jennifer Lawrence, Nicholas Hoult in a lot of ways. That's not a knock on the new guys. The new guys all did amazing in their roles.
But the biggest reason why the main trilogy cast is better:
Iconic Xavier, older Magneto, Wolverine, Storm, Jean Grey, Cyclops, Rogue, Kitty Pryde, bad Mystique > young Xavier and Magneto that don't look like their comic book counterparts, Havok, Banshee, Angel Salvatore, Darwin, lovey dovey BFF Mystique
One of these screams X-Men. The other one, not so much.