LFD was by far one of the most catastrophic features to ever have been implemented in World of Warcrafts history, and completely defeats the purpose of having classic servers in the first place. The core audience who fought for classic wanted them precisely to move away from the instant gratification, antisocial, and un-immersive features that have littered modern WoW. This applies to WOTLK as well. LFD did not exist for the vast majority of WOTLK’s lifespan, it wasn’t added until ICC and wasn’t a part of the original experience until the very tail end of the expansion.
A core part of the classic experience (and that includes most of WOTLK’s history), is that you have to make connections and build relationships to get things done in the game effectively. LFD kills this aspect of the game and forces everyone to sit afk in a lobby. Auto teleport to the instance further decimates the open world and is blatantly non-immersive; it reduces the game from being a full blown virtual world to a lobby. Cross-realm auto grouping destroys any accountability of the players, and 99% of the time you are never going to see any of the people in your group again. This notion that the game should cater to solo players who don’t want to find a guild or make any friends in the game is a modern retail mentality that has no place in the classic game, and retail already exists for these players. Furthermore, most of the time queueing as a dps really doesn’t take much longer to get a group than forming your own group. If you don’t have any friends to invite, then you have to whisper around on /who and eventually you get some takers. The only time you are really saving is traveling to the dungeon, but that only takes 5 minutes with epic flying mounts. Queueing in only a time saver for people on dead servers. Dead servers are of course a problem, but LFD only treats the ailment and not the underlying disease. The solution is to merge dying servers, not pull the plug on the core classic experience.
Blizzard has zero to gain by catering to the loud kicking and screaming minority who want retail features in the classic game. 99% of them will either continue playing while simultaneously whining about the lack of LFD as they have been doing the past 3 years, or move back to retail. Literally no lost customers by not catering to this audience.
On the other hand, if LFD is added into the game on launch, 99% of the core classic audience will quit. If these players are lost, classic wow is simply not profitable and the classic playerbase will die since they will have gone the route of catering to loud the minority who is playing retail or would play retail anyways if classic did not exist.
If the plug is going to be pulled on classic after WOTLK ends, or WOTLK is going to move on to cataclysm, then at the very least LFD can be put off until ICC as it was originally.
On the other hand, if we get the pipe dream of a WOTLK+ or classic+ expansion, LFD should never be implemented into the game. A tolerable compromise could be to add a more user-friendly group finder tool that already exists in the current tbc realms, but LFD will result in the mass unsubscriptions of the entire core audience of classic.