[Inconspicuous Kitty]

To be honest, the primary issues as I see it are:
1) Fox skills are greviously overused when compared to the other styles, specifically expanding ice - actually, mostly entirely expanding ice;
2) Icicle Spear sees no use due to the setup it requires, with Crawling Spikes similarly seeing rare use
3) And comparing Hare/Bear styles to Fox, it deals comparatively little damage, as fox style deals magic damage, something harder to resist, and factors in elemental attack.

I personally am a fan of Chaos #2 suggestion to get Hare style back in gear, though I'm not sure I entirely agree with being able to attack with one momentum at full damage being a great idea. I enjoy Chimera style as it is, as it's not very overbearing, but still strong; rarely seeing use as it is. I don't consider two momentum particularly strong when you have to expend three to make those other two strikes off.

As for Icicle Spear, I frankly wouldn't mind seeing Frozen added to it's status effects, but I'm not sure it will still see much use compared to the other two Fox Styles, regardless. Perhaps as an alternative, it can be used without guard up, but with a slight damage nerf and no inflictions?

EDIT: I cannot form a thought today. tl;dr Fox skills used too much, power balance issue more than anything.