Traits/speacial power or potion effect that last for the world

Okay so what my idea is, The Player gets a menu with a extensive list to choose a effect that will stay with them in that world(single player).

On a server it could be permanent and the only way to change it is to pay money which would also balance PVP(making it very serious choice on servers.)

and of course if you want to play as a normal player then you can.

I'll be honest I got this idea from the fact that my Aquatic looking Character whose Lord of the Squids can't breath underwater and that stunts my Roleplay.

and to balance stuff like that you could add a weakness or catch, for instance, The water breathing, with simple code you could add the catch that though you breath underwater and mine faster, you also can't breath air and must stay aquatic in order to stay alive, this would make resource collect to be much harder when it comes to land resources.

My point is that you guys could revolutionize Gameplay in Minecraft.