I was hoping the sorcerer would turn out to be the spell-point based arcane spellcaster (aka an arcane spellcaster using a psion-like point system).

This would make them mechanically different than the wizard in a nifty way. Also, such a mechanic would fluff well with the "you can cast spells ... just because" explanation. They could provide some fluff examples to give people some ideas on how they might want to expand the "just because" part if the players are so inclined to add such detail to their characters or campaign.