A lot is going to depend on the fluff. All we really have to go by at this point is a name and rough physical description. They made Tieflings into a true-breeding race with history and culture after all. They got their own weapon designs, even. I'd be shocked if they don't do something similar with dragonborne.
As far as comparing them to Lizardmen, it occurs to me that Wizards has kind of been neglecting classic lizardfolk for a while now. There are precious few actual Lizardfolk mini's out there, for instance. They don't show up in modules much either, probably because they make poor antagonists. They're neutral, and so almost always get a sympathetic potrayal that lends itself more to diplomacy than swordplay. (This rule holds true even in most of the D&D based video games I can think of.)
On the other hand, they aren't well suited to being player characters either, so they end up being mostly background material. I can see a well done dragonborne race as mostly supplanting lizardmen as the ambiguously aligned lizard-race that can be either friend or foe. Eberron already depicts lizardmen with a vauge draconic connection. "Blackscale" lizardfolk are the chosen servants of a Black dragon who happen to have acid resistance, for example...The Dragonshard RTS game (which flopped, but had to get all their fluff approved) had an entire faction of dragon reverencing lizardmen, including two champions who had overt dragon characteristics.
Trogs on the other hand have gotten quite a bit of love in the last few years. I can see Wizards continuing to push them as the evil lizard-race players should have no qualms about fighting.