I did all LFD groups, never felt frustrated, though that might be because I was a tank the whole time and I'd built a series of clickable macros that posted strats to anyone who didn't know what they were doing.
This makes perfect sense. The thing is, not all LFD tanks are/were like that
Heroic scenarios... really, Blizzard? Most boring aspect of wow put on the front burner. You literally have to bribe your playerbase into running them (50 valor for the first scenario per day) while your devs openly admit they don't really know "where scenarios quite fit into the game yet".
Horrible, horrible, horrible idea.
Why not just make new 5 mans that award extra valor instead?
I'll sign whatever petition you give me that will reimplement 5man dungeons.