The current plan is to allow players to use their flying mounts once a character hits level 77 in Northrend. I understand you feel they don't add to aspects of the game that you are looking for, but we believe they do add to the game and we are building the new content with the ability to use them in mind.
You will be able to use the same mounts that you currently use in Outland. There will be some sort of process to complete to be able to use the mount once a character hits level 77, but the exact details are undecided at this time. If you are referring to needing a large sum of gold to use them, sort of like a new tier of flying skill, that isn't the current plan.
source: curse
