Let me help you out with that one. In this post Krutoj admits to never having played with the dungeon finder in retail. Quote:
No I didn’t try the random dungeon finder in Retail. But I had a lot of fun with the RDF on Warmane.
To give him the benefit of the doubt he may just refer to current retail. It would make sense since he’s an avid denier of history.
I doubt this, to be honest. I think it is precisely the cross-server aspect many people want. That’s why they insist on the social aspect not existing, and why some even try to make the argument that the cross-server dungeon finder is more social even when that claim can be disproved by a quick skip over to retail.
It is true that cross-server would solve many issues in the game. But that’s true for everything. Had they had cross-server sharding from the get-go then maybe we wouldn’t see the monofaction mega-servers that we do today. However, maybe the opposite would be true as well – if we had had zero cross-server functions (i.e. no cross-realm battleground) then maybe that would have made the balanced servers seem all the more appealing. Because you would not have been able to do Battlegrounds on a monofaction server (assuming same faction BGs wasn’t a thing either). Sadly, that’s probably a hypothesis we’ll never get to test. Not in WoW, at any rate.