I am a vet of UO and actively read your UOHall forums. Honestly I keep one account open in that world but mainly my time is here in Azeroth.
The pvp aspect of the game will be for someone else to describe as I am a pve'er and not much into pvp yet. I left actively playing UO have 84 months at the end of 05 and have been here since. I love it.
Graphics? Out of this world compared to your Harry Potter pic there. Yes it seems at times the armor/clothes are painted on our PC's but the depth and expansiveness of this world is huge.
The only thing I would ask before entering WoW is to remember, WoW and UO are not alike, try to avoid comparing the two. Learn the aspects of WoW and give it an honest try. Some don't enjoy it at all.
But at least Bliz has art designers that can make an attractive, usuable UI. One other thing I like about this game over UO, is that Bliz understands each player is uniquely different and allows custom user inferfaces to be installed and utillized in game, there are literally thousands of addons that is Bliz approved. Give the game a try, know you'll always have a special place for UO in your gaming heart, and get ready to have fun.
Lastly, the 'ol level grind arguement, bah. Yes characters are working to get to the next even level for new spells/skills etc, but the game is so well balanced, whether you are 15th or 59th, you are truely surrounded by a world that matches your skill range. They did a brilliant design on the world.
Welcome to WoW, and if you choose the server, Kirin Tor. Whisper Brumble and I'll help you however I can.
Bo