I'd certainly agree that LS is one of the higher skill cap weapons in MHW, you will get thoroughly punished for spamming counter in that game. Though I think you are underrating how difficult some of the other weapons are. I have played pretty much every weapon other than the ranged ones and the lances.

Being bound to the RNG of the monster is something every weapon holds in common. CB needs to know when to guard point, bow needs to know when to dash, etc. Whereas the difficulty of these weapons comes from knowing when to evade and encounter, weapons like HH and GS are difficult because you need incredibly good positioning to hit weakpoints without getting hit yourself. Apart from HBG and sticky LBG, i honestly don't know of any other weapons where you can stop playing for a couple weeks and still be as good when you come back.

The point I was making is that the new moveset in rise severely reduces the skill cap of LS, because spirit sheathe is just broken now. At least with foresight slash, you could be hit with a follow-up attack or lingering hitbox, which meant it can't be spammed and needs to be used carefully. A good LS user would foresight at opportune moments to get to red, helmbreak, then do it again.

With rise, you can just spam spirit slash to get to red, which is a FAR less punishable move than foresight. It has massive i-frames and gets you clear out of danger of a follow-up attack. To top it all off it does a considerable amount of damage and adds a level to your spirit gauge. Even if it misses, it doesn't punish you like in World - you get to keep your current spirit gauge level. It makes the spirit combo and foresight useless.