There's.. well, a lot that you've missed! There's several new classes and previous classes have been tweaked. Many different areas to train, more equipment available for those past lvl 120, etc.
As for switching servers, it's your call. Unfortunately, I don't think that the character transfer ticket is available anymore, but if you like playing as a hermit, you can just make one in a different server and you can get up to the lvl 90 range pretty quickly, especially since there's a quest line that you can do that allows you to get from 1 to 60 pretty quickly if I recall correctly.
The monster park is an excellent way to get some levels before lvl 100, but you'll have to hunt for ripped zebra tickets in order to use the park.