Well no... it's not just how they cast spells is different. Mike said it himself... there are different sorcerer heritages for the power they wield. One inhabits their draconic ancestry, one has inate magic that explodes wildly out of them. There's a story to why they have power and how they wield it, which is completely different from the book-study of the wizard.
I'm sure there will be mechanical differences, but this is sounding A LOT like the sorcerer from 13th Age.
I guess my question is, to cast like a sorcerer, does that mean I'll have to take the sorcerer class with all of that extra sorcerer flavor? I thought lots of different casting options were going to be included in the wizard class. And, if is isn't, then what else is going to be its own class? Sorcerer Points really have no interest for me, but I like the idea of working with a more limited spell-base for more casual games. The article, after all, talked about a very specific flavor for wizard spellcasting - vancian. Am I just behind on this, and missed where they said they were doing away with that idea? Will there be a spellcasting class for all the different types of spellcasting?
I guess my question is, to cast like a sorcerer, does that mean I'll have to take the sorcerer class with all of that extra sorcerer flavor?
I wonder if they went back on their original plan, and wizards are just vancian.
But, in that case, is the Vancian mechanisms are removed from the game, or the Wizard class redesigned so that some Wizards can bypass them, then the need for the Sorcerer class disappears. In which case it should just be removed - it was a mechanical artifact, so if mechanical changes make it redundant then it can go.
The DMG or somesuch is likely to have a lot of different spellcasting modules, which you might apply to one class, or all classes, or several classes, as is your game's wont. At minimum, we'll probably at least have a points system (psionics!) that is adaptable for any spellcaster you might want to have it.
In fact, one key point of this could be to design every spellcasting system with reference to the same daily slots table (what Mearls mentioned in today's article, i.e. the Sorcerer uses the same daily table as the Wizard). This is the best starting point, because it's a common ground to all spellcasters. Then Wizardry vs Sorcerer vs other subsystems can be balanced together around this table (eventually some subsystem may in fact even grant additional slots), and then be "swappable" between different classes, something that at least several people seemed to like when it was talked about in the second-last playtest package.