SAM tweaks "I" would like to see.

[Shurrikhan]

Tweak 1: Remove Kaiten

I'd rather not. It flows well, is about the final component keeping the Kenki gauge relevant now that Guren/Senei cost 25, and the last thing I'd want is just less Kenki or even more Shinten spam, especially now that Seigan is gone.

Just remove the ability to reapply it while it's already active.

Tweak 2: Combine Iaijutsu and Tsubame-gaeshi

This would take more than the typical button-consolidation behavior or you wouldn't be able to track Tsubame-Gaeshi. I'd prefer they be consolidated only for so long as one doesn't manually put Tsubame-Gaeshi on their bars (at which point they split) and that it show the CD for Tsubame-Gaeshi even while revealing (and not darkening even on TG cooldown) the readied Iaijutsu.

Combine Ikishoten and Ogi Namakiri

Yes, definitely.

Tweak 4: Remove Kenki cost of Gyoten and Yaten

No. They are clearly attacks. They don't need the Thunderclap treatment. And they cost you only 8 potency (Shinten has an efficiency of 10.8 potency per Kenki, vs. GT/YT's 10.0).

I have to disagree about Kaiten giving you more to think about. The only difference between it being there and not being there is that you wait till you have 35 Kenki to use Shinten rather than 25 Kenki. But to each their own I guess

The difference is from Shoha. It increases the value of each Iaijutsu by 193.3 potency (or 66.7n for Shoha II), but that potency does not scale with Kaiten. This can give some very niche situations by which a normally inferior choice of Iaijutsu may be worth rushing out without Kaiten (since the Kaiten on them wouldn't be as efficient as Shinten) in order to finish off your Meditation stacks, such as before a boss jump for which you could Meditate back to full.