'What a game can't have' and 'what a game won't have' are two different things.
I didn't think you could have Kazuya fight well in a 2D plane, but we've seen otherwise.
Likewise, you say you can't have fireballs in Tekken, I say you can. Look at MK vs DC. Sure, bad example but you're looking at fireballs from a SF perspective. Look at them from a Tekken perspective.
Ryu uses a fireball, you sidestep, problem solved.