I think a better way to reduce damage variance due to crit is to make Midare(+Kaeshi) and Senei double-hits, akin to Dream Within a Dream and Barrage. Those two were picked because their animations show (at least) 2 hits.

I guess people would disagree over whether Midares hitting for "25k!!25k!!" feels more or less impactful/fun than the current "33k!!" (with 6.08's "50k!!" as a reference), but at least crit synergy would be restored.

Midare+Kaeshi makes up about 20% of SAM's damage and reducing the variance on that alone should solve most of it. Ogi+Kaeshi can revert to single 990 potency hits without introducing too much variance because it makes up 6-7%, plus doing so also keeps the full impact on SAM's largest single hit.