The simple point is that you always choose groups of powers that are WAY too multi-faceted. What's more, they're often not related by any kind of theme. And they promise that, when developed, you're nearly to reality-bender status (or at least, the status of a powerful mage).
“…Judge not what a man has done, but judge what he could have done if he was a different bloke altogether. For art thou a leper? And a leper can changeth his spots…” --Rudy Wade, Misfits (Series 4, Episode 8)