I have played every season and think classes are very well balanced in comparison to prior seasons.
Just a few notes: Every class seems like it has a niche and a role in the ro-Sham-Bo table.
Cleric is really tanky but has no chase potential great for area denial
Fighter/barb: has decent dps/tankyness
Rogue: has poison tipped and rat-rogue for looting decent agility bonuses
Ranger……..range is underwhelming but is decent against mage.
Mage: mage sucks without good gear but is impossible to catch outside of rogue/ranger
A big improvement over last season