One thing I am absolutely tired of seeing is people walking around with Firelord/dragonslayer/Fearless etc titles with skyscreamers and what not mounts and when you inspect them and see their achievements, they got it AFTER the content had passed which is completely unacceptable. If you were not able to complete the content while it was relevant then in my opinion you do not deserve to get it. To let these amazing things still be obtainable after the content has been nerfed/out-dated demotivates players to get it while it is current therefor slowly destroying the game and causing it to become more stale.
This is the typical thought of most players who get these things- "Hmm, instead of finding a guild and actually trying to kill H Sha of Fear so I can get the amazing fearless title, I'll just wait 1 or 2 more tier until it is nerfed and the newest gear can carry me through it"
^^^ Things like these is what is destroying heroic raider prestige these days and it is sickening to my eyes.
imo the meta mounts and titles should be made completely unobtainable after the tier has passed and all the battle pet and mount drops should be nerfed to >1%
I believe this will actually motivate players to actually engage in this content while it is relevant instead of waiting until it is outdated and facerolling it therefor improving the quality of the game.