You cannot forbid rubberworm, it has already been officially integrated into the next beta (all features except Kawoosh's new ones - this is planned yet).
Arrows - lol, it's an absolutely harmless feature (except the Darkness mode). And you cannot prevent its usage anyway: there's an easy trick - play an offline game and enable /arrows, go back into menu, don't quit WA. Arrows will be always enabled without a notification until you fully exit WA.
When also forbid custom worm names. Every Worm has to be Worm 1, 2, 3 etc. it is unfair!
We can discuss about it infinitely and forbid new and new simplicity ways, most of which cannot anyway be prevented. But somehow I like your idea.