I've been thinking about this a bit more. The more I think about it the more I think the devs should seriously consider a version of ion_frigate's idea, and wanted to make one last bid for it.
The biggest wrinkle is accounting for the difference between movement and attack delay, but it now occurs to me that there's a really simple way to do it: just multiply final, post-AC damage by {movement delay/attack delay}, in basically the same way brands multiply it by a constant range. So I imagine something implemented (and described) roughly as follows:
Battle Dance
At * piety, Uskayaw grants followers the grace and agility necessary to blend movement and attacking into a fluid martial dance. Whenever you move into a square as a result of your normal movement or Line Pass, you automatically attack each opponent that is adjacent to the square you move into. Your damage is significantly influenced by your momentum and the speed with which you can bring your weapon to bear; as a result, you are deadlier with faster weapons than slower ones, doing damage at the same rate you would if standing still.
imo this has pretty much everything going for it:
- Anyone who's played roguelikes with similar abilities knows they're fluid, tactical, and fun. This is especially true when there are other factors making positioning important--something Usk's other abilities do beautifully.
- It's an excellent thematic fit, and reinforces Usk's ability to offer a distinctive play style (which I guess is pretty much the main point of the god).
- It has neat, and in some cases subtle, synergies with all of Usk's later abilities--it helps you approach creatures for quick stabs with Solo Time, and encourages you to seek out the right clusters of enemies for Pain Bond (and in advanced cases manipulate them into clustering in the ways you want).
- It overlaps with cleaving just the right amount. Melee worshippers without axes get the necessary AoE attack, but Battle Dance still leaves axes with a niche: it usually doesn't hit quite as many creatures as cleaving does, and it's useless when you're surrounded. (otoh Battle Dance is a great mechanism for avoiding getting surrounded in the first place, and then there's Line Pass.)
- It doesn't raise any complications with riposte or reach weapons. (It does significantly reduce the situations in which you'd want to use reaching, but I don't think that's a very big deal.)
While the ability still favors melee, substantial amounts of Usk play suggest to me that this isn't a problem. Offensive spellcasters are already really great at AoE damage, and get piety very quickly. And even they would get some use out of the ability, since they too need to move sometimes.