Tonight there’s a black market/costume event going on Feralas. In and around the Ruins of Isilden. While most of the businesses are run by Horde races, everyone’s welcome! Just remember to bring your Elixir of Tongues!
The Warcraft is a Stage Discord/Tumblr group also regularly hosts events.
There’s also a Google Event Calendar.
And of course all the Guilds that are recruiting and running events. You can see the threads updated here on the regular. Come check out the Firebrand Enterprises thread, where I post our planned events every week!
Kalimdor and Eastern Kingdoms are already big places, but since then we’ve seen the addition of Outland, Northrend, Pandaria, the Draenor, the Broken Isles, and Zandalar/Kul Tiras. The world is soooo big now that the odds of just randomly bumping into someone out on an adventure keeps decreasing. Being able to fly everywhere doesn’t help either.
If you’re looking for RP, you have to go where they are. In the major cities, to guilds set up in specific areas- like the Shadowtusk Tribe in Zul Gurub, Heart of the Raven in Tol Barad, or the Southfury Watch in the Barrens- or to pre-planned events you see advertised or through word of mouth.