There are two reasons that can pretty much sum up why I am unsatisfied with hit points in Next: you do not start with enough, and you are largely reliant on magic to get them back.
When I tried running Age of Worms in 3rd Edition several months ago, the characters ended up having to rest every few rooms due to the lack of a cleric. In my Next campaign Hit Dice have made things a bit smoother, but ultimately it depends on how many cure wounds spells the druid and ranger have on tap.
The talk of a variety of hit point modules is good, I guess, so long as at least one of them lets you play without having to have magical healing. I think I have said before that my ideal hit point system would be something like the vitality- and wound-point split that I first saw in 3rd Edition's Unearthed Arcana (and that I maybe saw later in one of the Star Wars games), where wound points are based on your Constitution score, and vitality points are derived from class.
Wound points would recover more slowly over time, maybe based on your Constitution modifier. Certain attacks like poison, maybe critical hits, could directly apply to wound points. Vitality points would recover much more quickly, being the more abstract part generally reflected by combat skill, luck, etc. Things like warlord "shouts" could be used to recover them in combat, as well. I would also do something like Dragon Age: Origins, where getting reduced to zero wound points slaps you with a persistent injury that recovers over time.
As for halfling barbarians, I think that 4th Edition did oddball combinations best by making it so that while certain race/class combinations were more ideal, the rest were still capable of contributing in a meaningful manner. Like, a half-orc barbarian would probably start out with a Strength score of 18, but the benchmark was 16, which a halfling could still do. The ironic downside with Next is that given the 20 cap on ability scores, even before all the talk of stat-boosting feats, everyone will end up with the same score no matter their size category.
Humans used to be a very fun race to play because you got a variety of floating bonuses. Now its just a bonus to all your stats, and...that is it. Pretty easy to build with, but really boring. I do not think that humans should just be the "speed-building" race, especially when it means that they are as strong, tough, fast, smart, wise, etc as other races that are supposed to have those traits as a shtick.