Who's more powerful? That's still up for debate.
The main reason
I like sorcerers is for the fact that they don't have to constantly change their spells to fight a battle. If I
think I have my mage's spells memorized for the upcoming battle and half-way through I realize that I have one or two of the wrong spells, I don't have to change my spell selection. Then when I fight the same battle and I this time I need a different spell, I have to repeat selecting what spells I think I need.
With a sorcerer, as long as I have that level spell available to cast, I can cast any spell of that level. I don't have to change my list.
They are both extremely powerful at high levels. IMHO, if a high level sorcerer and a high level specialist mage got into a fight, whoever gets off the first spell will probably win.
What you call a curtain of laziness, I call convenience.
