Do you expect, if i spent 20k ingots in this wheel without getting him that i spend them there again next time, unless there's another reason to do it thar has nothing to do with Minato?

If instead i got once 10 frags and the following time 20 or viceversa then i would indeed go on spending ingots here next times too, knowing that if i get 50/60 here while also getting the redeemable side rewards then i can compete him in another event, spending some coupons to buy the missing 20/30 frags.

That's the point.

What oasis should do is to replace the 80 frags with a pack that drops half as often as the 1 frag of kisame that, by opening it, gives a chance to get 1/5/10/20/80 fragments randomly, like the coupons pack or the ss pack of lucky dices.

This thing would work and would be loved by everybody (you still have the chance to get the full ninja, but even if you don't get it you are fine with consolation rewards).

The event drops grasps and kisame samehada frags with quite a high chance. If you go for naruto or any other full ninja they will place there in the redemption side it's almost granted by spending 25k there that you get a full 80 frags of kisame, 300+ grasps and also a good number of ss.

There's no reason to place a full ninja there just to make fun of whoever doesn't get it since you will spend in the event regardless if training potions and naruto six paths/edo itachi/edo deidara/kakuzu eg continue to appear there.