Okay, as it stands i got 2 templates for a Grand Majin build, one is based on maximization of AoE skills while the other is completely focused on spin.
AoE build


Spin Build


While for grinding purposes the more buffed spin only build seems the better choice (especially below lv40 when you don't have the other AoE's yet), i'm afraid that on higher level and especially if spin gets nerfed that build will not suffice.

Sadly with the AoE oriented build there's not much room to get the KD/def buff nor the shield buff which both are deed into the two buff columns.
In both cases i've put 1 point into the Special Surprise Punch since this serves as a nice quick ranged pull.

Hyper bomb sucks now, I wouldn't put 5 points, I would just keep it 2/5 if I wanted to get Special Surprise Punch.

Hyper Bomb isn't usefull as a damaging skill, however it decreases the physical attack of every single target affected by the DoT by about 60% (instead of 30% at lv1).
Which is the main reason i took it.

Ah I see, that's understandable than.

Hmm, with some testing on the test server it would seem that on higher level spin only lacks DPS to do any proper damage, as a farming only build it might still work but not to actively play with it.

The 2nd Grand Majin AoE has a casting time, making it ill-suited for when you're tanking aswell.