I absolutely despise this line of thinking that "casual = bad". I think Blizzard owe their long-time players to have some progression path for people with limited time, but who still have the skills.
Something like Leveling > Normal Dungeons > Heroic Dungeons
Where heroic dungeons are endgame and properly tuned and treated as such. Not all of us itch to raid. Not because we do not want to, but because the time it takes to find a viable raiding guild that suits and unpredictable gaming schedule is significant.