>>57396864I think /tg/ would give you better answers.
I've played a few card games and I'd say that the more mechanically similar to MTG the game is, the less likely it is to slip out from its shadow and establish its own niche. People rarely play multiple card games, they tend to specialize since a tcg rewards that. If you spread yourself thin over multiple games you probably won't have enough of the good stuff to excel in any of them unless you're some kind of super Kaiba. If a game is really similar to magic, why not just play magic? There's been a ton of games that have shared table space over the years, but the most enduring outside of MTG have been pokemon, YGO, until the FF fuck up L5R and more recently Lorecana. I've watched Score DBZ, The Spoils, WoW tcg, and Key Forge just wither away. You have to distinguish yourself as a product and game or MTG eats you, just like WoW eats any MMO not named City of Heroes. So while you could have a mana system, the biggest card game in the world already does that, so you'll have to do something better AND beat the magic momentum.