You said it yourself the only way Blizzard can get people to be social temporarily is if they try to force it.
But in all seriousness after the initial setup TBC Classic is going to be just as not social as retail is, and retail is still pretty social if you find a guild or community and choose to interact with it. Outside of my guild, TBC Classic isn't very social for me and neither was the original TBC. "Tank LF H [Dungeon]" - Then once the group is formed I hit my marking macro to explain the marks to everyone. On particularly complicated pulls I might type out a quick explanation. This isn't a discussion and it isn't being social. It's just telling the group what needs to happen. When the group is over some people will add me to their friend list in order to bug me the second I log in to come tank for them.
If I need something from crafting I'll type "LF [profession] w/ [recipe] my mats + tip."
This is the extent of my social interaction with people outside of my guild. This is how it was in original TBC as well. Guild chat is mostly observations about the game and Discord is mostly memes. Just like in retail.
Group quests are harder, and people have to manually make dungeon groups. That's really about it.