For the next X-men show-My 2 Cents...
This is some advice I would give to whoever is producing the next X-men series, whenever it comes up-
1. Remain true to the spirit of the franchise. X-men has always been about fighting discrimination and about an impending war between two species competing for dominance of the world. It SHOULD NOT be turned into your average superhero slugfest. The X-men aren't really superheroes...they're more like a kind of peacekeeping force...soldiers fighting to prevent a war.
2. Wolverine is no doubt a major character but he SHOULD NOT be the 'star of the show' but must in fact be used sparingly. He does not even need to appear in every episode. Also, when he does appear the focus should be more on his relations with the rest of the team and how they affect his personality. Wolverine's relationships with Shadowcat and Rogue, his flirtations with Jean, his rivalry with Cyclops etc. Also, he shouldnt be a wild maniac eternally tearing things and people apart...Wolverine in the comics eventually became a far more tempered man, a disciplined warrior, and thats the side of him they should portray.
3. I would like to see more focus on Xavier as the heart and soul of the X-men. Somehow I feel there never is much focus on the creator of the X-men as much of the focus is on his students kicking ass on the field. I'd like to see Xavier portrayed as an active member of the X-men, if not in the field, then at least behind the scenes as a strategist. He should comes across as a true visionary, a benevolent leader who genuinely wishes to help mutants and make the world a better place. He should be viewed as a revered figure by his followers though he can also be shown to be fallible and to have his faults.
4. Cyclops DEFINETLY needs to be made a much stronger character, a true leader of the X-men and devoted follower of Xavier's cause. He should be the guy who's able to coordinate the team and make it work. He should be the one guy whom everyone respects and looks up to. Even Wolverine should follow his orders (albeit reluctantly). And he shouldn't be completely emotionally dependent on Jean. In addition, I think Storm is someone else who would benefit from some character development as the second in command of the X-men.
5. For the tone of the show, I'd say it should be dark albeit with hints of optimism and brightness ala the Nolan Batman films. It certainly shouldn't be depressing.
6. Magneto should be shown as a foil to Xavier, a visionary like him except that he is one with far more extreme views who does not believe in human-mutant coexistence. Magneto and Xavier's relationship, both as friends and enemies is something that certainly must be delved into. Magneto should also be shown to be a benevolent leader in his own way, to his own people. Mystique on the other hand should be a complete badass, a terrorist who absolutely hates 'homo sapiens' and isn't really a visionary for the mutant race but is powered solely by her anger and by ulterior motives.
7. There should also be some focus on the X-men's lives and relationships outside the field.
As for the X-men lineup, my recommendations would be-
Professor Xavier, Cyclops, Jean Grey, Storm, Wolverine, Nightcrawler, Shadowcat, Iceman, Rogue, Colossus
Brotherhood of Mutants lineup-
Mystique, Avalanche, Sabertooth, Blob, Pyro
Magneto's Acoyltes-
Quicksilver, Scarlet Witch, Mastermind, Toad