And you find "they're lucky, optimistic, unambitious, and good at being out of the way" unsatisfactory, even though those might be directly responsive to the halfling mindset.
I'm not going to say that your wrong to be dissatisfied, but I'm also not sure it's really a "problem" with the halfling.
Actually, yes.
See, I mentioned this before, but this idea that halfling luck is partially derived from them being unambitious is a serious problem for me.
See, according to the book, their Goddess bends luck in their favor, but the real force behind their luck is that they are so unassuming and unambitious that the universe bends to protect them... except if that is true, then it means that the ambitions of the other races are the only reasons that they are attacked and killed by all of these violent and savage events.
If everyone was just a simple farmer with no ambitions beyond good food and friends, then nothing bad could happen to anyone in the world anymore. All of the misery or humans, elves and dwarves is all their own fault.
And this is despite the fact that, well, I found this in the halfling PHB write up about humans, "Humans are a lot like us, really. At least some of them are. Step out of the castles and keeps, go talk to the farmers and herders and you’ll find good, solid folk. Not that there’s anything wrong with the barons and soldiers—you have to admire their conviction.
And by protecting their own lands, they protect us as well.”
Humans have ambitions, they have castles and barons and soldiers. Because of that they can't have the idyllic luck and paradise of the halflings, but even the halflings acknowledge that by having those ambitions, those castles, those soldiers, the humans are protecting the halflings.
Earlier in the thread people asked what was wrong with halflings being one of the core four races. To me, this is it. This is a fundamental problem. Elves, Dwarves, Humans they are independent. They survive and thrive on their own. Halflings? They need to be protected by their bigger neighbors, so they can remain idyllic, so that they are lucky enough to be protected from attack.
As written, that doesn't work.