Well I do believe there will have to be hubs of some kind. If the rumors are true and we have our own ship, we'll likely need a place for repairs and maintenance. That being said, what would make a hub feel more "real" or "lifelike" in your opinion?
I totally agree on that. There was something about being in our own unique hive of scum and villainy that really drove home the sci fi feels.
Eventually, someone is going to make the first game in which populated areas feel like real, populated areas, rather than video game locales. I think Assassin's Creed has already done this, but that isn't an RPG, and has a lot of resources built toward achieving that feel.
In terms of BioWare, I'd like to see NPCs going about their lives, rather than standing in the same places, unchanging, for a quarter or third of the game. Static NPCs that are basically wallpaper, and NPCs that seem to be hanging around in hopes that the PC will stumble upon them, are feeling very dated, at this point.
I really have no idea what type of investment it requires to achieve more lifelike environments in this fashion. Maybe it's not worth it. All I know is that I haven't really been impressed by any of the series' hubs, beyond the curiosity accompanying my first visit.
You could extend this to the general environments, too. DAI featured lots of enemies standing around in the wilderness, just waiting to be discovered and killed by the Inquisitor. Very lame. I never want to see that in ME. That really hasn't been a problem, and I doubt it will become an issue.