Blizzard started mailing out the Blizzcon 2013 pet to Virtual Ticket holders yesterday! So awesome :D
Convention attendees will probably have to wait until they receive their goodie bag to redeem their own Murkalot, but unlike Virtual Ticket holders, they can trade/sell the pet card that contains the Murkalot code. So it balances out in the end. Some receive the pet early but cannot exchange the pet at all, while others who receive it later and retain the option to sell it.
Speaking of balance...
There's some discussion on the WarcraftPets forums on Murkalot's battling ability. So far, it appears that his attacks and moveset leans toward being "overpowered". That isn't to say, though, that there aren't any ways or pets to counter Murkalot. I'm sure people will find ways around this pet. However, one can already tell that this will be a popular pet in PVP for a while, and may make the game frustrating for many players. Heck, simply leveling this pet has shown its many, MANY strengths.
On top of that, if this pet is truly "too good" in PVP, there will be the issue of "paying to win" that will need to be addressed. Once the majority of the PVP endgame is filled with Murkalots, it will be the new status quo to have one on your team, or risk being at a disadvantage. This pet costs $40, so although some may want to keep up with the rest, they might be unable to or unwilling to shell out the money to do so. I can see this causing a lot of friction in the community.
On the other hand, now that Murkalot has been released, IF its abilities get nerfed there will be some who are upset that they paid for the pet, expecting an overpowered contender in pet PVP. Again, the trouble of "paying to win" situations.
We'll see how things go for Murkalot, but there are really only two ways this can go: the pet gets nerfed, and some are upset that they paid for it to use in endgame PVP OR the pet doesn't get nerfed, and pet PVP becomes a game of who can play Murkalot best or pair him with the best team. One option will cause a ripple for a while before things cooldown, and the other will cause frustration until the next "OP" pet is released. My best guess is that Murkalot will get an update to his abilities and won't be a "must have" in pet PVP in the near future.