Mael'Keth is tuned so a level-30s party can win: 22,000 HP and 265 Strength. A level-32 party wins a little under half its fights.
The five floors before every Old God grow tougher, up to +25% HP and damage on the floor before the god.
A god's War Cry and similar buffs last three rounds instead of the whole fight, and the intro screen shows the HP the god really has.
Dialogue answers before a god fight now apply, and damage and defence answers count for the whole party.
Monster special attacks on companions are softened like normal hits, a god's ability aimed at a companion is its normal attack, and tanks protect themselves before they taunt.
Items waiting for room in your pack reach alt characters, can no longer be lost, and arrive when you open /boss. Bequests from teams reach the team's leader (for older teams, once an admin has set the leader).
The Inn lists every patron, not just the first eight, and you can find someone by name.
In PvP, frost slows instead of freezing, and stuns, sleeps and freezes can no longer be chained.