You know, why don't we just make our own system for TFHs? I suspect that there's enough know-how here in regards to design and plenty of play-testers.
It would certainly be possible to do that, its just generally a matter of whether it is worth starting from scratch or if it is a better idea to rework another system to fit. As for if you really want to follow through with a custom approach here are a few musings I have had regarding the idea of a system generically based on fighting games. (I am a novice in terms of actually playing them, so it may be a bit off)
- Simultaneous action selection is a must to get the right flow, otherwise the combat system starts falling apart as you can decide to just counter the opponent's strong moves at your convenience leading to combat being a slog
- Given Simultaneous action selection requires some sort of conditional resolution, ie what your action does depends on what action the opponent does.
- To improve flow 6-7 actions is the absolute maximum number of options where things get out of hand
- A good baseline to start working with in terms of actions are: Attack>Feint>Block>Attack + Special
- Three approaches to character customization would be: Combos- Bonuses conditional to playing specific actions in a certain order; Styles - Either provide multiple choices for each action type, or make upgraded versions of each to indicate a focus in that type of action; Specials - Essentially each character would ideally have a fully custom action that has limited use which can violate certain baseline rules
- Combat breaks down when things end up as anything besides 1v1, so the best approach to handle that is with an 'Assist' approach where the active player can use a weaker version of their ally's abilities (a mini special essentially)
- Narratively it is jarring to try fitting in your standard best of X fighting game structure, so either you would need to drop it entirely or replace it with a mechanic based on getting back up and continuing to fight.
Just a few samples to illustrate the suggested character customization concepts(these are only a fraction of the details that would be needed for a character, and probably aren't balanced correctly):
Frost -Reindeer of the Blizzard
Style: 3x Attack, 2x Attack+, 3x Feint, 3x Block
Combos:
- Bitter Blizzard: Attack,Attack,Attack+ - Opponent's next action must be Block
- Black Ice: Attack,Attack+,Block - Opponent's action resolves with themselves as the target
Special: Frostburn - x1 Damage vs Block, x2 damage vs Attack, x2 damage vs feint
Assist: Frostbite - x1 Damage vs Block, x1 damage vs Attack, x1 damage vs feint
Montana - Cattle of the Hills
Style: 3x Attack, 3x Feint, 3x Block, 1x Block++
Combos:
- Pasture stance: Block,Block,Block - Heal X Units 1/combat
- By the Horns : Feint, Attack - (Interupt) Reset Opponent's combos
Special: Bullseye(Feint) - Negate Opponent's next action
Assist: Bull Market - Negate Opponent's next combo.
