Man, I'm rereading the Origins UA document and...there's plenty of lore to work with for the elves, dwarves, and gnomes. Dragonborn and Goliath are oddly light, but Dragonborn have all of dragon lore to draw upon, and since these Goliath are tied more strongly to giants (a mistake, IMO), I guess they have all that lore to draw upon. I'd prefer Goliaths get the same amount of lore as dwarves or gnomes, and at least keep the sense of fairplay, the love of high places (which is alluded to, but very vaguely), and competitiveness. That's plenty to hang your hat on, and makes them more interesting than "im a little frost giant".
Likewise, plenty there in the halfling, even if I strongly prefer the 4e traveller halflings and wish they'd stop trying to erase the idea of halflings having cultures that live like that, not just adventurous individuals.
Still. The fact that I dislike how wotc writes species lore, what ideas they latch onto and what they ignore, etc, doesn't mean they're doing something wrong or should change course to suit me. I can and will just write my own species lore to suit my preferences.
Hell, in my games Shadar-kai aren't elves, llolth doesn't exist and drow are literally just a regional ethnicity of elves, goliath and dragonborn have never been descended from giants and dragons and have instead always been separate species from them, gnomes are much more a mix of 4e and the 3.5 Races of Stone writeup mixed with a lot of ideas from Irish mythology about the successive waves of invasion that became the little folk in the hills over the centuries, fir bolg are the oldest mortal race and invented the first written language and are related to goliaths, and a host of other stuff.
I don't think wotc should make official dnd more like my dnd. That's my job.
Now, let's look at the A5e heritage writeups, which are excellent and are one of the things that make me want to try the game in spite of the things I don't like about it.
Dragonborn...has less lore than the UA Dragonborn writeup. If you add one of the Dragonborn related cultures, like Dragonbound, you get...roughly the same amount as the Dwarf writeup in the UA. The rest is mechanical features, in both cases.
Maybe it's a fluke. NOpe! It's all of them!
It's almost like certain folks have no problem whatsoever with a specific thing, and then treat it as a huge and terrible thing when wotc does the exact same thing. Wild!