I'm really glad that I leveled Aka immediately with Cata's release. The curious transition from the end of one xpac to the beginning of the next is so infrequent that the unique experiences it provides are pretty limited. I remember reading posts from people who were excited to venture into heroics or raids raw, without the experience of videos and guides, and develop a strat out of their mistakes. Without a standard, there was less pressure to adhere to it and more freedom to make mistakes. I like that freedom - the idea that you are doing the best you can with what you have and that's a point of pride.
Leveling in Cata brought this home for me in terms of gear. Not that I'm a gear snob - I long supported dungeon-geared players in Wrath heroics. I did not forget the fact that heroics are designed to be done by those in dungeon and quest blues, not just ICC-geared badge farmers. And yet, I spent so long upgrading between epics, rather than green --> blue --> purple, that I forgot to take pride in the freshly dinged end of the gearing spectrum. My personal standard went up, and I felt rather unenthusiastic about my pally - how could I dare to tank a dungeon when I didn't have enough badges to buy even one piece of respectable gear?
My disdain for greens followed me into Cata. Replace my heroic ICC25 legs with a quest green? People will smell my inadequacy a mile off! The turnover was high, too. Not only was I dropping my coveted epics for quest greens, but the greens themselves were very quickly replaced within a few quests. It reinforced my elitist view of greens: they were so impermanent as to be worthless!
The amazing thing was that because I had been taken down a peg by all these greens, when I got blue upgrades in regular dungeons, I was happy. I was ecstatic to then replace them with heroic blues or JP pieces. The BiS list that I had was not from H Cho'gall or something equally lofty, but just the best heroic blues or reputation epics I could get my hands on. When I look at my character pane, I am deeply proud of my assorted blues, the merits of my hard work, the best I can do with what's available to me. Even the epics I do have put me slightly above the expected par for raiding - not everyone has access or funds for crafted or dropped BOEs.
It's awesome to zone into a raid and be impressed not that guildies have some higher level epics than others, but rather that they have any epics at all. It's even better to down a boss wearing H blues, to then get epics for a lucky few in the raid. This is how the game was intended to be played, not with misplaced snobbery against those who dared zone into Naxx without full tier.