As far as utility goes...

They could make it so that using an Iaijutsu gives an AoE version of the buffs you have from Jinpu/Shifu possibly only at 50% effectiveness (I.e. 5% damage and 5% SkS)

Just a little passive utility while you're slicing through enemies. Alongside Slashing debuff where relevant.

Something I think would be cool would be a high Kenki spender CD like Guren, but that instantly grants all 3 Sen. Even better if it was another cast time skill like Iaijutsu. So that you can burst with high resources with Midare Setsugekka > this new Hissatsu > Midare Setsugekka (Though, the issue is wanting to Kaiten before every Iaijutsu which would not be possible if the new Hissatsu cost more than 60 Kenki...)

An alternative would be an additional Iaijutsu that also had a Kenki cost with it. So, say you had 3 Sen and 50+ Kenki you'd have access to this new Iaijutsu instead of Midare Setsugekka.

Outside of that, I'd personally like to see Meditate retuned to have more frontloaded impact. So it's more viable to use brief pauses in uptime to generate a bit of Kenki rather than it being kind of meh outside longer periods of downtime (That also don't require movement)

A buff to Seigan wouldn't go amiss either... Given that you have to be hit (With Third Eye) to be able to access the skill in the first place, 15 Kenki for 200 potency seems lacklustre given that 4 level prior to unlocking this skill you have Shinten which is 25 Kenki for 300 potency. That's a difference of 13.3 potency per Kenki vs 12 potency per Kenki. At the cost of being hit (Then not using Merciful Eyes for self heal if relevant) with a 15s CD because of Third Eye. Compared to the skill that's usable whenever...

Though, I suppose it's hard to balance because if it's too strong then you'll be wanting to walk into damage for max DPS... Kind of like what happened with DK's in WoW when they made AMS provide resources when it absorbed damage and made them all go running INTO AoE's to do more DPS to much frustration of healers >.>

Would probably be for the best to focus on defensive options from Open Eyes I guess...

On a side note:

Would be cool to have a charge up mobility skill. You know the one, like every depiction of Samurai has that stand off between 2 of them and then after a pause with both of them grabbing their katanas, they dash past each other and then one of them falls over. It was in the ShB trailer too, the part where it's a showdown between the WoL and Zenos.

Its place would be similar to the Yaten > Enpi combo where you back out and get bonus damage with your ranged skill before you head back in. Only instead of walking or using Gyoten, you can charge up a cool skill to reposition instead