I am an icon artist for v4. I think the following summons should be in the game.

MonkeyKingEnma- It should be able to turn into pole and fight as monkey too.

You should be able to learn it at level 300 after talking to ghost of sarutobi which should be hidden somewhere in the game(hard to find)

Manda-Orochimaru's strongest snake.

It should be in the game. It should be stronger than all other snakes. You should be able to ride it. Level 240 maybe

Umibozu- The water monster or whatever should be in too. Level 240



You should be able to learn two summons or erase your old one. This makes the game better. You should only be able to erase old summon twice. L