Given its status as a side activity in WoW, I approached it in a casual manner. I had a great time exploring the world, catching every new critter I saw. I loved chasing down as many rares as possible. I enjoyed most of the trainer battles, too. However, there came a point where it felt like a casual approach was no longer sufficient. The elemental trainers in Pandaria were difficult, but doable without too much effort. Past that, with things such as the Celestial Tournament, I lost interest. It's possible, in my casual approach, I totally missed simple ways to clear the tournament, but it seemed to me it was aimed toward players with a far more hardcore approach to their pet lineup. I decided to give the Tournament a pass and hang up my battler hat until Warlords.
I don't take any real issue with pet battles getting harder as an expansion draws on. That's the nature of game progression. I just made a personal choice not to delve too deep, because I knew the feature would lose its charm for me if I did. What about you? Did you participate in pet battles? What was your approach? Was the Celestial Tournament right up your alley? Did you take part in any PVP? PVP, not for me!