If I were you I'd go look at the official website specifically the announcements and code changes. There have been a LOT of changes since you played, some big some small.
One of the biggest was recently they made it so empowerment is NOT required for the priest classes. There are drawbacks like shaman without empowerment can't earn paths(OHH YEAH, they added shaman paths!) and unempowered paladins won't earn virtues. And if you're unempowered all your supps will be one level lower than you are. So at hero all your supps will only be lvl 50.
OHH! They made it so you get a slight exp bonus even if you're just a group of two. And they made it so mercenaries from a bunch of places will give you exp bonus as if they were another player in your group. "score damage" is one of the features that a lot of people, myself included, love.
They took fly away from healers and took transmute metal to wood from druids, that was a sad day. I see why they did it, but I personally would have handled it a bit differently.
My head is spinning trying to think of all the changes since 2005... There's a LOT!
Welcome back, and godspeed to you in your recovery.