Give him a secret skill: ultra rockomancy
Summons one rockoid at the end of your team for each enemy that died since he entered the battlefield.
And a passive: auto-acccelarate self
Every 100 secs it reduces the second cost of all his moves by 20%. Stackable 3 times
The move with rockoid summoning after teammate’s death has timber already but beter with 2 summon rockoids after teammate’s death.
The passive auto - accelerate self is confusing but ok. My opinion. 
Make dolph individual because he has no “partner legend” with the same moveset like flarevern and tiamazus, rexo and kami, dragaia and gf.
Give dolph a ssecret passive lol. And activr moves similar to icefang and burnsalot.
Really op movesets for a monster come on it has to be viable and balanced not some god monster
I think that dolphs moveset is great and nothing shoudl be changed. I use him for stunning monsters whitch could cause me problem like nox egg or bane etc…and sometimes you cant stun enemy because of protector then you can use proctector killer to get rid off this protector monster and also pretty good counter for sanctistag. I got few suggestions how to improve dolph but that would maybe changed it to OP monster. Timestrike > timestrike double (like Metathereion with sleep granade and double dreamhunt), passive skill: stun revenge or stun immune and secret skill: summon rockoids.
I LOVE the idea of stun revenge. In a stun team you would have to let him wreck havoc, or kill him, stunning your team