My prediction how things will turn out at level 60 respectively level 70
I believe within the 1-2 weeks time frame players will start reaching level 60, and probably level 70 within a few days. Once you got your level 60 pretty much everybody will hit the battlegrounds, seeing as the Grand Marshal set is far more superior compared to the dungeon gear (BLD, DM (W/E/N), Stratholme) thus rendering it useless. Also it is extremely cheap in conjunction with the 3.3.5 honor rates. My prediction is that one could gear up a toon from leveling greens into full epic Grand Marshal in a day or two (assuming that there is a steady flow of players queueing up for battlegrounds). Time wise we are about two weeks into the vanilla expansion now. So on the third week we will start seeing these messages floating around in the global channel "LFM AQ40, MUST BE FULL GRAND MARSHAL OR NO INV". Now, is this what we want to happen? Maybe it is, I don't actually know however, I personally DO NOT want this to be the case. There is a few solution to this, either: disable the set completely (I doubt it), increasing the honor required for each piece, decrease the honor rates, or my personal favorite setting an honorable kill requirement for each piece or completely swap the currency for the set to honorable kills. The latter option would work like the present arena rating requirements on the wrath realms (showing up as a red text in the items tooltip).
As for level 70 we don't have an equivalent to the Grand Marshal set (at least not to my knowledge) so we should be out of the woods there.
Buttom line, we DO NOT want this to occur.
PS: Being afterwise reading this through it had compleely slipped my mind that we actually got arenas available to us. So perhaps an ACTUAL arena rating requirement could be implamented for each piece. Now this would require people to actively queue up for arenas if we are to reach that 1.9k threshold. Or if we wanted it to be extremely rare you could combine all of the above suggestions making the set require: Honor (increased amount), HK's, arena rating and also nerfing the honor rates.