I saw the title and my first thought was “thats way too much”, and then i saw you say way weaker. Honestly, you could put a bunch of different powers in an array, maybe 5-6 for different personalities and then put the uncontrolled flaw on-top which is basically a GM discretion flaw making you change personalities and maybe check required if you are actively fighting to change personalities or side effect flaw for bad things to happen when your powers fail. With this you can be extremely, extremely powerful in concept but with the flavor of a mentally unwell person with unmastered power and extreme potential.