They do have the truck in their ears. But it's unlikely the director (or anyone in the truck) knows wrestling to that level. In football there are spotters next to the announcers to help identify players who make tackles, for instance, but it's hard to feed real-time, detailed information because while they can hear the broadcasters, the spotters/talent stats guys can't talk directly to them. If they gave it to him, it was via a written note. ESPN does more elaborate productions than just about anyone else, but the on-air talent needs to be prepared.
In a former life, I was involved in many live sports broadcasts. To me, DC seemed a bit disorganized and unprepared/uninformed about the basics of the event names, brackets, etc., but his strategic commentary, energy and insights were decent-to-good. He doesn't do this a lot, so that would explain some of it. Rock really helped guide him along, IMO.
All of that said, ESPN probably doesn't care about any of the DC's professional broadcaster shortcomings. DC isn't really there for anything other than cross-promotion, to be a hype man. Rock Harrison is the guy for the more refined commentary.
IMO all of the analysts have their quirks, but Harrison is the best of that group since he stopped sounding like a referee training seminar and quit the, "a takedown is felt" stuff. Seems to me that he now simply describes what he saw and, when necessary, goes into the rule book to explain.
ESPN (and CBS, FOX, NBC, etc.) goes into their events with a storyline and they don't often deviate from it. They discuss it in pre-production meetings and are trying to thread it together with each element of the broadcast: intros, players to watch, interviews, etc. It all serves to tell the story. This year, ESPN is hyping their MMA coverage as part of that, it seems.
This is why the game/event productions are pretty darn good, even if the storylines are annoying to some fanbases. If it seems like they're talking more favorably about one team or wrestler, they probably are because they've prepared features and segments of the broadcast around those ideas. It's not because they hate your favorite school.