My wish, even though I doubt it could happen, for more reasons than one.

Kaiten- Auto-Crits (like Life-Surge). Alternatively, changed to 60-70% damage bonus as opposed to the current 50%.

Third Eye- Open Eyes buff does not disappear upon usage of Merciful Eyes, OR Seigan, meaning you can use them more than once. Shorten buff timer to maybe 15 seconds instead of 30.

Hagakure- Sen consumption no longer required. Kenki generated flattened out to 40 or so, every usage.

Meditation- Grant 20 Kenki on activation, keep Kenki regen as a bonus effect, like it currently works.

Flat potency buffs here and there.