Soo no normal level dungeons to do between leveling? That's the dumbest idea I've ever heard.
If any difficulty should be removed, it's heroic. Heroic is only relevant the first week or 2 of the expansion. Once Normal/LFR raids open up heroic is forgotten, while Mythic still has incentive for people to run every week (hydrocores, Glory achievements, mount drops, etc).
Hell, I and many others just skipped heroic and went straight to Mythic when we got to about 300 ilvl. I didn't step foot into a heroic until after I had ran all 9/10 mythics that I could, and that was only like 1 or 2 runs just to replace some shitty boots or something that I couldn't currently get from WQs