So basically, the Wither Storm could randomly stop eating the world and focus on consuming animals and mobs for some time.
This could especially help with performance during the 6-7 phases. Could be configurable in the settings if needed.

Forgot to add that the Wither would also keep on trying to kill the player as well as other entities.

bro is gonna become a tornado instead of a Wither Storm

Ermm.. what

I'd rather not do this since it may seem weird during the larger phases why the Wither Storm has suddenly stopped picking stuff up. I think it's multitasking makes sense since the command block is theoretically doing all the heavy lifting with the block clusters while the wither itself is targeting and eating mobs.