I agree—I highly doubt that there will be a considerable social cost if housing is added, especially since most antisocial players already have all the tools and incentive to be antisocial anyways. Group and raid finder already did in socializing in the game and limited group formation, which was generally the core of it outside of guilds.
#1 Hype-Thread Shitposter - Overlord of the Hypethread
I do wonder if it would be worth it to get a private sever of my own for sandbox purposes since I want to generally screw around with mapmaking and proof of concepts. Is it worth it to do so? It seems like it's not illegal or anything when used for private purposes.
Even Ion, who is seemingly completely disinterested in transmog, still wears prestige items. The Scarab Lord title, the Lightbringer tabard, the Precious' Ribbon... player housing is an extension of that. In a good system, a trained eye should be able to pick out "prestige" items that are associated with specific tasks, from gold sinks to raid kills.
I don't exactly know if we're allowed to mention the name of a private server on here, but there's one that specifically lets you build your own places. You can also visit other places that people have made if they're public. There's a huge RP community there, but if you just want to build, you can focus on that.
Admittedly, that would be a little different, although I'm far from of the belief that player housing is a bad idea—I do think that those things are a little more visible and mobile, whereas player housing is generally individual and isolated. I could see that working if others are allowed in your houses, though, either as guild halls or individual homes.

Mate, I've got long hair too, and I would shave my head for a playable, updated Gilneas with a world quest system in it. Never loved a zone's vibe more, and never been sadder to see a zone so quickly fade into irrelevancy. A revamped Lordaeron/Gilneas/North-Eastern Kingdoms might be my #1 most desired expansion theme.
Well that'll never happen.
Most likely what they'd do is just plop it in, blow up that unused bit of mountain that's causing clipping issues, and maybe pare back some of the tress on the back side of Ambermill or w/e that place the mages have in Silverpine is called.
Then throw in a road that connects it down to the old Hillsbrad Farms (and maybe blow up the Sludge Fens that it became) and then be like "job's done."
FFXIV - Maduin (Dynamis DC)
I don't really have any interest in housing, but without any functionality/utility other than private training dummies and crafting stations there would still probably be a ton of interest from people from all walks of content. They'd only make it a hated feature if it became mandatory. And if they start small and modest but design for easy expansion it might not be a huge drain on development resources to introduce it even if it flopped completely. This is a big thing in other MMOs, I don't think WoW players are uniquely uninterested.
If it's like other games with housing there'll develop a sizable community. Plenty of people roam around the houses in FF14 (and many players set them up as 'shops' and social hubs. My wife's first floor is basically a bakery.
I remember back in vanilla I was in a guild that treated one of the empty taverns in the park district as their tavern. Had weekly events and everything.
I kind of miss that general idea of empty spaces that players can make their own. It really feels like 'everything must have a purpose' now and it kind of sucks.
The average player was doing fine in vanilla and TBC. Wrath, though, single handedly ruined - yes ruined - players' expectations of what challenging 5 men was and ought to be.
Any self respecting player that disagreed with that assessment at the time only did so because the content was so mind numbingly easy that they just wanted to get out of there fast.
However, you go ahead and try to rectify something that was obviously problematic and you shoot yourself in the foot, because now you've given everyone a nice sizeable taste of how... convenient the gogogogogo "system" was and now no one wants anything but that.
Much like with flying. "Hey, here's flying at max lvl. Just use some gold and fly away". Years later, "yea, we'll still have flying in the game, but you'll go through different, long stages to get it".
There you go, a split playerbase.
I absolutely wanted housing back then. I came from Ultima Online and it was just part of an MMO to me.
Nowadays... I still think it's a good idea, but my feelings on it have gotten a lot more complicated.
I used to hate any instanced housing system. To me the whole point of a house in an MMO was to feel like you were living in the world. Obviously, as MMOs got mainstream, that stopped being feasible just on a practical level, but the culmination for me no longer wishing for that was Shroud of the Avatar. That game tried to compromise a bit, where the game world was not explored freely, but on a map. In this way, players could make villages, that would appear on that map. This allowed for there to be both a way to instance the housing into those villages, but put them on the map like any other location so they felt equally like a part of the open world.
I liked that idea. The problem, for me, was that every one of these villages I visited were min-maxed for the sake of showcasing the player vendors. When every village in your medieval fantasy game looks like a shopping mall from Second Life, I didn't feel like I was playing a game anymore.
Of course, part of that also relates to how much control you have over the housing, which can be another complex topic. Personally, I would like something in-between. Too little control over the house or the decorations and it all sort of feels pointless (especially when it's instanced), too much and I'm never going to feel like I can actually make anything with it unless I hire someone to help me.
I think it could really breathe new life into World of Warcraft though. In the past, Blizzard has experimented with things like the Music Rolls or Battle Pets in old dungeons or zones. Player housing would be a way to do that permanently and perpetually. I mean, who is going to go back and get a Music Roll for their one-expansion-only Garrison? Music Rolls for player housing, however, is something that would be permanently meaningful content. There are a million things you could add this way, from little doodads, to Music Rolls, to mounted heads of old bosses to put on your wall, the possibilities are endless.
It absolutely needs to be personal though. Guild Halls always sound like a good idea, but I've never seen them implemented in a way that doesn't just create awkward have and have-not systems that arbitrarily punish different kinds of players. One of the most common ways this happens is by not having any of the Guild Hall stuff scale. In other words, the big guilds have no problem maxing everything out instantly, but a smaller guild of close friends can basically never actually do anything with their Guild Hall, if they can ever afford to build/buy one to begin with.
I farm up music rolls for my apartment in my guild's house in FF14! It's a lot of fun, and trust me when I say it's a hugely popular thing to farm for, alongside appearances and pets. (And a guild hall in that game is the same price/plot of land as a large house, so is generally reachable eventually by most guilds.) (just address the difficulty in getting a house, and it would be perfect imo)
And in lotro I was able to afford a guild house for a tiny 3-person guild relatively easily. So it can be done. And in both games most players generally focus on making things look cool rather than be efficient or min-maxing (I remember the towns in SWG, very heavily focused around vendors)
In Lotro you can put crafting benches and the like into houses. I still see a lot of activity at the crafting areas in the cities though, so I don't think it really affected that kind of thing too much. Maybe a solution in WoW would be an area inside a neighborhood for crafting. Phase it in a way where it's shared with all the neighborhoods so players can still be social and see each other.
Either that or simply don't allow it.
ETA: Having an instanced apartment in a guild hall for players would in fact be something they absolutely need to lift. Give a player a room, much cheaper than a house, and inside their guild house.