Arguing semantics never looks good. Some games call it LFG, other Group Finders. Most modern MMOs have an automated version and a version for those that really want to be nitpicky about their groups.
See, no. They already have instanced infrastructure in place and it would run off infrastructure already in place. There is no further cost to maintaining it unless you seriously think that adding an extra row in a database whenever new instanced content is added even remotely qualifies as that. In which case, please move on.
It really wouldn't. It worked just fine in WoW: TBC albeit it wouldn't let you define roles and that was its major downfall and the reason few used it. Other than that it wouldn't teleport you and everyone went to the dungeon they queued for. You're just making up excuses.
Uhm, hello. Yes, the search function runs client side. Your client is the one that pings the server if more people are looking for the same thing - it's not the server pinging the client. The server just maintains an array of people currently in a queue - nothing more.
I have done raids, oh no. You need a DPS with Toughness. Oh my. Oh no. Whatever shall we do. How about.. Just having an extra role for Raids. Such difficulty.
You really can, instead of talking to an NPC inside which sets the variable for the dungeon path, the dungeon finder does it for you. Again, this is basic stuff you learn the first year of software engineering. As I have said, these automated systems have worked before - there's no reason why they can't work again.
The LFG Tool is useless. A group finder, LFG or whatever you feel like calling it would make it easier on all parties involved. I know that, you know that. I don't see why you're even trying to debate this.
Not everyone is comfortable making a listing, because making a listing also implies you will lead the group and an amazing amount of people do not like such pressure put on them.
I suspect you're the same kind of peeps that believe World of Warcraft "died" because they made an automated LFG. Except that opened up the game to millions of people. You sure do advocate the same silly reasons as they do.