Nerfing additional stats would impact 0 in actual PVP unless you want every fight to last 10 rounds and unbalance the game even more by making 200 k players struggling against let's say 120k. In my opinion those stats are working fine for PVP reasoning. By decreasing refine values of them the only thing you will gain is less power for matches against let's say ninja exams chars. The 100 difference in those stats will stay the same as nerf works for everyone. You will get just a bit less of them which is bad overall in game mechanics. The game is already made well by devs regarding this.

That's how should be. Every game online has such secondary stats and in order to reduce that damage you should stack that stat aswell. In future after all ninjas from a lineup will have let's say level 10 refines and a closer approach to their oponents those stats won t seem to work like the way You described. In this actual phase of the game a move 2 to 3-4 will be teared apart by an stacked Kushimaru. That's how it is right now. Imo those stats work good and shouldn' t be nerfed. As about differences between players (aka move 1 vs lower other part's) is another story and as long as 3 category of players exists in here like in every online game business there will be descrepancies but this is not an suficient reason to nerf the mechanics.

In time You will see it won't be so unbalanced.

As a conclusion we should get the sun/moon coins shop faster :) where we can gather enough advance refines or other power items for those coins.