a draconic bloodline (more then one?) or wild magic. Spell slots look the same as the wizard (which we knew?), spells known about the same as warlock. Spells suggested also classic wizard spells, which again we knew?
Like the very open and flavorful approach to their origins.
So they took a class whose whole raison d'être in 3e was different caster mechanics, and made it mechanically identical to the 5e wizard. Biggest disappointment in 5e. Those of us who don't like vancian casting (which I believe was a majority in their playtest polls) can wait until the DMG comes out in November to see if they give us a paragraph blurb about spell points as an optional rule many DMs won't kinks about or want to hassle with.
Well, at least the art is cool.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.