Samurai is in a pretty rough spot in Crystal Conflict, especially with regards to the other melees. And it comes to two things: their Limit Break is a noob stomper, but really really bad vs good players; and they have to cast for like 4 seconds to lay in their burst.
I would be okay with the way the limit break works, if they had a bit better ability to lay in the dps normally. And I would be okay with the cast times if, again, they had a bit better ability to lay in their dps.
To that end, I think one or both of the following changes should be made:
Midare Setsugekka should ignore Guard (like Drill does).
Ogi (and Kaeshi) Namikiri should not get a 50% damage buff for single target hits, but instead ignore guard for single target hits.
This would give Samurai some much needed ability to actually hurt their target, as well as a niche in the melee dps ranks.