Theory Crafting - Swift Charge etc

Hey guys,
Was just thinking about following skills, which could implement some new mechaincs.
A - Slot for the same stats as Swift Sparrow, Sturdy Blow etc.
Effect would be something like this:
"Grants + X/X per attack, Bonuses remain for the rest of the fight and are capped at +Y/Y"
Y would be probably after 3 attacks. My main idea behind this was to reach higher stats boosts compared to plain A-skills like LD and Fury without penalties or Phase restrictions. Therefore the boost would build up during a fight instead of being active from the beginning. This skill type would be interesting for longer fights like RD or for tanky or duelist type of heroes.

Also thought about a similar skill for Dancers with a different aim for the skill:
Dancer's charge
"Every time Dance or Sing is used this unit is granted +X/X/Y/Y"
But not for the remainder of the fight. Depending if be all stats will be booted or if two different skills for offensive and defensive Play style exist, it would be resetted after the next fight (all stats) or the next attack (offensive stats) or the next fight initiated by a foe (defensive stats). E.g. "every time Dance or Sing is used this unit is granted +2 atk/spd/def/res. This Bonus is resetted after every fight with an enemy"
Main idea behind this would be to use a dancer first for what is made giving his turn for another hero and by this getting stronger so that he can survive better or score 1 deadly blow in the 3rd or 4th turn.

Hope you like the ideas and feel free to comment. :)