[Ranylyn]

There's numerous uses for the skill. It's not something to use every turn, definitely, but with smart, tactical use, it's a godsend as is, and I feel that lowering the Momentum would just make it something people use every turn and push it over the top.

For example, say you Sidecut through a physically-oriented enemy, ending adjecent to them, and then use Repel on them. The Repel crits, pushing the enemy to a comfortable distance. At this point, you have a few options: You can Crystal Rose, Couloir, Cyclone Spear, Kazekiri or Hirakuzi away the last of your momentum for a solid hit, or use something from your subclass... or use Sheath Sword. "But why the hell would you even use Sheath Sword!? Hidden Cut sucks!" It does, but you're completely overlooking the other, and far more important, facet of the skill:

Sheath Sword provides a guaranteed counterattack that can trigger at the same time as Riposte. If the momentum cost was lowered, they'd effectively have a 1M attack they can use once per turn, and hidden cut pushes it ever so slightly over the top with free damage as is. If you personally can't work it into your strategy, then don't use it. It doesn't need to become ludicrously unbalanced simply to make it more appealing.