One thing that really stands out - it's a pretty darn caster-friendly enhancement tree! And that's fine, sure, but it really seems to be lacking anything that really stands out at all as far as the active or passive abilities. A lot of racial trees have some pretty remarkable stuff here or there - sneak attack dice in halfling, boost for human, a whole enhancement tree splash as elf/half-elf, dilettantes.. warforged get their weapon attachment, fortifications..
I'm just sayin', really, dragonborn feels kinda.. flat?
The breath weapon is neat! But it only scales effectively for a caster with metamagics and relevant spellpowers. Why not also have a melee-friendly scaling component or option? And I really feel like the entire tree just needs.. something. The breath is 'neat' but just doesn't have any 'oomph', and while I get the utility of a movement ability can be maybe remarkable for some builds, it just doesn't feel remotely 'defining' as an upper tier enhancement!
I'd love to see just a little somethin' more, something that stands out, for dragonborn enhancements. I'm totally cool with it being a very caster-heavy tree with a little splash of defense as far as passives, but it's almost nothing but!