One of the more unwelcome changes in the latest Wrath Beta build is pretty simply explained: It now takes nearly twice as much experience (80% appears to be the exact number) to level. This has hit a few us on the WoW Insider Beta team by surprise. Both Zach and I, for example, were about 2 bubbles each from our next level, and now find ourselves only halfway through instead.
Of course, this is the Beta, so one can hardly complain about one's leveling time stretching. However, 80% is a very significant jump. It would imply that either Blizzard was intentionally keeping leveling experience incredibly low so they could get testers to max level quicker, or they felt that testers were leveling far too quickly and required a massive amount of slowing down.
I doubt leveling will be slow as it was in the bad old days of games like Everquest, but if it's so slow that players need to clear both starting zones to level up enough to progress further, it seems like that defeats the whole purposes of having 2 starting zones in the first place. Hopefully Blizzard monitors this new changes and adjusts it downward again if needed.