I don't think a dungeon finder is the solution but they need to have some better LFG tools. I would like something a lot more obvious and varied.
Ideally, the LFG tag should come with a set of filters, that when you set yourself as LFG you can then highlight any of the quests you have in your log that you are LFG for, rather than just write a comment (though that option should remain).
Then those looking for people to join their group should be able to search the LFG list server-wide (not just by planet) and sort it according to the quests people have selected. This would making finding people for specific heroics and flashpoints a lot of easier when they are spread out.
We should also have a role option, when you set LFG it should allow you to pick one of the three roles and show this as well, which again would make finding each other a lot easier.
A system like this would be a vast improvement over the current one and maintain the social element of actually having to talk to people to form a group. People would also contain to spam the chat channels on the Republic Fleet, so it wouldn't hurt that "social" element either.
But it needs to be obvious, like a HUGE button next your character portrait on the main UI. Otherwise no one will use it.
I couldn't agree more.