That is actually smarter way to handle those.
Truth to be told both wildshape and polymorph in vanilla 5e both OP and utterly dull.
You get tons of extra hp, but you stuck in a useless body of beast. With absolutely no option to polymorph into something more useful.

Would be nice if Larian would try to homebrew polymorph and wildshape to be more similar to PF2e. Those both provide far great options for shifting, and well balanced.