Hi Buufen,
The majority of players on private servers prefer and expect a higher experience rate. The main complaints I saw coming from players of retail was that it was far too slow and grindy to level up your character and that it was too expensive to get premium items, but that's not really related to your post.
Spunny is right though, it does get tougher to level up as you progress to a higher level, but still much much faster than on retail. We have plenty of high level content here unlike retail, so that's where most players want to be, not stuck levelling for months
Anyway, I hope you enjoy your stay here.