I think 5 man being so easy is really because Blizzard go from one extreme to another. People disliked how easy WoTLK heroics got so they made them more difficult for Cata. After people complained about those, they hit them all with a giant nerf bat. They seem to be unable to find a middle ground. Hopefully WoD solves this by having fairly easy normal dungeons but tougher heroic version of them.
You have 4 hour LFR runs? Yikes. The problem with huge, long dungeons, while I would love them personally, the majority just don't want them anymore. I would LOVE to see stuff like BRD again with the same kind of size and number of bosses. People just don't have patience these days, imo. It's exactly why people are so hostile to new players, or players who might get one thing wrong or even when someone asks for help or advice. They now think everything should be done super fast and that everyone should know everything about the game. The community is it's own worst enemy in terms of actual community and improving the game for everyone. Too many have an "it's my way or no way" attitude to stuff. It's why you'll likely never see huge 2 hours long dungeons again. And it's a shame, really.
I've never had a LFR run take me 3/4 hours to complete. And casual players will actually be busy doing something else while they wait for their queue to pop. They don't all just sit there and twiddle their thumbs. There are also too many bad players hiding under the casual tag. These are likely to be the players that complain the most about things that most casuals are actually happy with. Casuals enjoy challenge. They have skill. Well, not all of them but you get what I mean xD
I think I just rambled about nothing there lol It's late and I'm tired
I know what I mean at least lol