Well it worked quite well in some regards on WoW.
and im sure there are a lot of people who are against it (usually those on high pop realms) and those all for it (usually those on low/medium pop realms, which seems to be a majority imo)
anyways. make the LFG system cross realm, its a good idea for Australians (like me) playing in the afternoon/night local time, but being like 2am+ shard time. when nobody is online, my fiance and i were in queue on the dungeon finder for 4-5 hours before we got sick of it and logged off. we queue up as soon as we log on and would be nice to do the dungeons
babbling on.

TLDNR; Make LFG Cross Shard, it would benefit many those who dont like questing or pvp and just want to dungeon