the sorc still requires material components to cast spells from their "innate power".....LITERALLY UNPLAYABLE! (in seriousness mechanically its not a big deal but flavorwise I have never understood it. Just let sorcs count themselves as an arcane focus when cast sorc spells, aka ACTUAL innate magic!)
I think the sorc rage is fine but it still seems a bit tacked on (do the subclasses modify it at all?). Maybe some sorc spells will further modify it. I mean +1 DC is +1 DC, but it seems weird to add this new class feature as kind of a new centerpiece for the sorc and for the vast majority of the sorcs time, that's literally all it does.
The brass tax will come down to the metamagics, depending on how those look will greatly impact how good the sorc looks overall.