Definitely hoping that at the very least we can obtain a base in Baldur’s Gate. Even better if there’s a possibility of this being linked to our past in the city if we lived there, though I guess Larian could easily fudge that as our previous abode having been destroyed in the course of one of the tragedies that have befallen the city. And I definitely want to meet folk we knew if we did come from there, as per benbaxter’s post.
Picking up another strand of this thread, my ideal would be that we can flesh out our custom Tavs in different ways and have the game respond to that (or choose to remain an enigma if none of the options it gives us fit). I think a mix of picking stuff at character creation - where it can help us crystallise our character and how to play them - and dialogue options that then let us get into detail and roleplay our choices might work best if Larian seriously attempt this. Which I’m not really expecting them too but would love it if they did.
For example, I might play a druid. Perhaps they’re an initiate into the Shadow Druids. Perhaps they’re from the Emerald Grove or have visited it in the past, or have at least heard of it and Halsin. I’m a ranger, perhaps I or whoever I’m working for knows something about a spate of mass abductions or disorder caused by a new cult and I’ve been looking into it. As a cleric, my temple might have been disturbed by news of a new deity, or someone pretending to be one. As a rogue (or criminal), I might be attached to the Baldur’s Gate thieves guild, the Shadow Thieves or even the Zhentarim in a junior capacity, or be an independent operator potentially with knowledge of people in these factions. And so on and so on. Then, more generally, do I have family or loved ones, and if so is there a worry they might have been abducted and caught up in the crash too?
I think Larian considering all the various ways our custom Tavs could be connected to the story, places and characters and giving us chances to express them (optionally!) in dialogue would do a huge amount to bring them to life. With perhaps some stuff like faction affiliation and where we’re from specified at character creation. I don’t think it should take a
huge amount of extra work in the game, either, just - admittedly quite a few - extra lines of dialogue to add flavour in certain contexts. The same basic stuff could still happen, and even things like faction affiliation wouldn’t necessarily make a big difference, just give certain PCs a head start in joining factions others can get in with anyway. Or mean that those factions are a bit more annoyed with us than they’d otherwise be if we go against them. And obviously things like family or lovers and so on would need to be fudged, with them either dying, having gone elsewhere or just living a long way away.
But still, that’s my dream (though by no means what I’m realistically expecting) for custom PCs in BG3. A home is the very least of it, and something I’d happily forego if I got some of that other stuff

.