There is both great news and bad news with the Sam changes for 5.0

Double Midare can be quite satisfying, I mean... roughly 2400potency in a single GCD can be neat (I expect that the second Midare is meant to be channeled during the GCD of the first one, since it's an ability instead of a Weaponskill. If not it does loose some of its appeal). Single target Guren with 1250Potency is good too, gives us more choice without a huge change.

What does makes me... Curious, to say the least, is the removal of Hagakure (40sec cd) for another one that gives 50kenki and has a 60sec cooldown without the sen removal. Meikyo gets a 60sec cooldown too now, which makes everything line up in theory for raid burst... Or does it ?

I mean, did the old rotation lined up a Midare perfectly every 60 seconds ? I don't recall so. Furthermore, the fact that we're locked without the opportunity to remove extra-Sen does remove a lot of flexibility in the gameplay.

Will it feel really good to line up the whole burst in a trick attack window ? Hell yeah it will.

Will it be almost impossible to do every time if you don't have the exact amount of SkS ? I'm more than certain of it.

Or except if Meikyo's function now is only tied to making sure we get all our Sen at once just for this burst window ? Probably, given its new 60sec cooldown.

I don't really dislike most of the new stuff. Even the new 80 ability (while quite low in potency for what it requires -> A full Meditate) can be usefull sometimes.
Although I'm not sure I like losing a way to perfectly synchronise with your group's burst window even if it means more burst potential on paper.

Sam will not be bad, but it will surely be akward in a lot of group situations now where timing and the ability to sync with your group are really needed.

Also, yeah, 2 or 3 sen opener, even some 1 sen openers will be even more of a pain now because we'll have to use an empty Midare just to "reset" the Sen counter during the start of the fight... Except if they make Sen disappear if we're out of combat for too long. (Meditate could prevent Sen from disappearing, which would make such an amazing use of this ability too).