See Greycloud Duelist.

Daring concept, top-down design. I didn't like the idea of daring working on either attacking or blocking, so I split the mechanic into attacking and blocking. Maybe separating the two is just pointless.

A mechanic worse than Frenzy is going to be a bit of a hard sell.

The way to do it, probably, would be to have the set give further bonuses to low toughness. Stuff that can regenerate only low-toughness creatures, etc.

Noted.

The set this was envisioned for doesn't feel like it has any iconic tropes that can be made into top-down mechanics. I'll have to work on some themes from a bottom-up perspective, and then let the world fit the ideas.