Here is an idea.
Three game difficulty modes. Hard, Medium, Easy. You choose which type of server you want to start on, but know you can only switch at the beginning of a new expansion OR downward in difficulty.
On Easy (Normal) mode, everyone gets flying instantly and the rewards are comparable to Normal Mode and LFR.
On Heroic mode, as is currently.
On Hard (Mythic), all those hardcore players can hash it out.
Of course there would be a Warmode option.
Oh, and you cannot interact with people in different upwardly, but you can downwardly with scaling. If someone on Mythic mode, parties with a Normal mode, they get normal more rewards.
Normal or easy mode does not get any special rewards or drops, it is so damn easy you can just use white hits. We call it baby sitter mode, for kids, you know?
Would you accept that?