General

http://www.basilmarket.com/forum/2881777

Note that the actual damage % values are different than the JMST values in that thread. I've posted updated numbers in response to others' threads, such as here:
http://www.basilmarket.com/forum/2893663

EDIT: Here's an abbreviated version with the main points:

-Mastery up to 95%, VERY early
-Attacking/killing mobs gives "sword energy" which is consumed when using Summer Rain/its Battoujutsu counterpart.
-Battoujutsu is now a toggled beginner skill, changes the way your main attack skills behave. GMS calls this "quick-draw" stance. Boasts higher crit rate, higher attack speed, and increased boss damage. Not having this active also disables forward crawling with attacks.
-Shinsoku is now a keydown skill. It hits twice instead of 10 times, but attacks ~5 times per second (much faster healing). Its +1 hit hyper now is monstrously powerful since it's a 50% overall DPS increase at all levels of funding.
-1v1 version of Sanrenzan is available, providing the ability to jumpcast single-target damage reliably
-Hitokiri is entirely unchanged.
-New 4th job skill causes all targets hit to take 20% more damage (multiplicative with all other effects).

the hayato forums here have it, scroll down and look for it, but theres no actual videos that hold importance because no jms hayato lv 200+ bothered making a video