If it's a competitive game for everyone then it's fine.That will be good,but even if you add payment methods,just don't make too op for those who got bucks.Make the game unique and competitive for all.
Man really gl to your game,but every mmo game is p2w,many people don't even join when they see that money wins (get super ittems fast etc.) when normal ppl have to wait and do missions all time etc.