Each battle that you win will yield experience for each pet that participated. However, deceased companions will not receive any experience (so make an effort to keep them alive by swaping in a different pet). Experience gains are based on your pet's level compared to the wild pet. Defeating a higher level opponent will grant more experience than a much lower level one, but be ready for a tough fight!
When hovering over an ability, the tooltip will tell you whether or not that attack is weak or strong against certain pet types. Additionally, you can hover over the opposing team's pets and view their attacks during combat. This will be important since it’s a good idea to pit a pet that's strong against the opponent's pet who's vulnerable to that type.
I made some route changes to the Horde levels 43-44 sections. I have swapped 44 Dustwallow Marsh with 44 Desolace (the entire sections). This allowed me to do Deadmire (at lvl 43 instead of 38) and then go stop at TB to turn in Deadmire + The Black Shield at the same time, then fly quickly to do the Desolace stuff. Doing 44 Desolace is now mandatory because I think its faster with the new routes. This will also make the level 53 grind much shorter. I think these were great changes.
World of Warcraft (also known as WoW) players have highly requested the classic version of their favourite game. As with any game, changes and major updates are added over the years. Since August 2006, many changes to the game have not been received well: such as trivialising levelling up. The level cap will drop from 120 to 60, but contrary to how that sounds, it will be a far more grindy journey of fun and progress. The current developers have made levelling up very fast in comparison to the classic days, purely to focus on end-game content and raiding which many people do not enjoy. Prior to these changes, many people enjoyed the games for years whilst not hitting max level, something never seen in the modern edition of World of Warcraft. The levelling process was a journey, having fun with professions and the grind that is no longer found. Of course, there are countless other changes that will be reverted, as you might expect when comparing something from 2006 to 2019.