I think I'm not alone in saying they really need to move on from fourth and fifth iterations of characters in this game. With such a vast pool of characters to draw from, I find it ridiculous that some classic characters have no cards at all, while others have a handful, while they're more often than not, just basic improvements on the previous card numerically and usually with the same ability (though with better chances to activate with higher rarities typically).
I know that since this is no unique idea, there's probably a few blogs circulating in this vein, but I figured rather than just listing characters I wanted, I'd try and actually do true card concepts as best as I can. I'm still new to the game (I only joined some time late December), so the numbers may take some time, but the rest of it should be easy enough.
[X-Man] Nate Grey[]

Rarity: Ultimate Rare
Power Requirement: 32
Sale Price: 244,800
Maximum Card Level: 70
Maximum Mastery Level: 45
Quote: Nathaniel Grey was artificially created by Mr. Sinister using genetic material from Cyclops and Jean Grey, with the hopes of creating the ultimate mutant weapon in order to dethrone Apocalypse as High Lord.
Base: 3120 / 3000
Maximum: 9008 / 8300
Mastery Bonus: 1228 / 1030
General Information
Alignment: Tactics
Gender: Male
Faction: Super Hero
Ability: Super Psionics
Usage: Average
Effect: Extremely intensify ATK of your cards.
So, I'll probably not do evolved forms just yet...or if I do come back to edit this thing, then I'll not use another picture, mostly because I don't feel like looking for another good one lol. I'm also going to try and structure the rarities based mostly on power (since in the game, the higher rarity pretty much always means it's more powerful), and I think in that way, they made the game somewhat silly, and not entirely by a comic-reader perspective.
It makes some sense that Hulk would have a UR/Legendary card. He's that powerful. Phoenix Force probably should as well. Nate Grey, is/was an Omega level mutant, so I think he fits. I don't believe Iron Man, Spider-Man, or Wolverine should fit that mold quite frankly, but whatever. It's just a game, and it's certainly only my opinion, and I've been behind my comic reading since probably the early 2000s, so a lot has probably changed since then.
I also realize that with the current limitations on deck size (which I think is a mistake on Mobage's part frankly) this isn't really much of a collectible card game unfortunately, so even though there are cards I'd like to conceive, because of stuff I've previously stated, I don't know how likely it is anyone would be interested since they would be lower rarity...but, heck, they're just concept cards for a reason. Not as though they're actually asking for ideas lol.
Anyways, I hope somebody other than me finds this relatively interesting, though I know it adds nothing to the game.