I can only hope that
This could always change in a future patch, but this is how it will go out with MoP.
means they are just planing to disable it at first, and let it go live later, with 5.1 for example, when most people would have already leveled their way up on their own.
If your referring to a specific rare quality version of a low lv pet then yes your correct. but then again if you know its gonna be re-enabled any way the "lazy" people will most likely wait for that and just grab the necessary pets for the achievements in the mean time and wait till ah trading is activated again.
If you mean with leveling (the quest line aka beating the trainers) then your wrong
why? you can still cage the vendor pets and put them on the ah so the lazy people (you know the one blizz was complaining about) will still be able to buy some normal max lv pets of the ah (or if your smart only one and you rush to pandaria and grab some high lv pets and them port back to your AH and put max level vendor pet back (the one you bought in the first place) back on the AH for the next lazy bum to pick it up) and circumvent the whole system anyway :S
there are 2 camps atm
first camp thinks people buying of the AH are trying to circumvent initial leveling so that those people can breeze thought the "content"
other camp thinks that putting rares on the ah is devaluing the whole aspect of the collecting.
Case 1 will still happen with the current solution and while the legitimate people are still leveling and grieving each other in the low lv areas for the rare spawns the ones with the max level pets will most likely comb out pandaria, northrend, outlands grabbing the rares while there still not contested, and them move to the low level zones with there high level pets and with luck the low level trainers have moved out of the zone by then.
Case 2 cant really see why people are bothered with that there are already rares on the AH now we even get a Black market as well. and people are fine with that.
If its the level thing simple revered the pets back to lv 1 when caged.
If its the flooding of the AH make the rare spawns and the rare versions of the pets more rare more in line with other rare pets we can buy on the ah atm.
Or make a simple restriction on the buyer side when it comes to learning the pet.
If its the achievement thing about the X amount of pets. Make only the uncommon version count towards the achievement.
for the ones that not care about that they still be happy with their grey version of the pet and for the people that do want to put some effort in they have to hunt for the uncommon version or if you leave the rare version how it is atm bump it even up to rare quality version of the pet to make it count towards the achievement.
SO many options to do without butchering the whole trading aspect of it.