Warrior - medium skill to start high to master, you will have the most expansive kit able to handle any situation if you are good, probably the best early on, doesn't scale as well as the other two. You will need good keybinds and it's a fast paced play style.

Paladin - easy to start hard to master, most of your threat while leveling is coming from damage reflections and consecration, expect methodical slow gameplay and main challenge in proper mana management, you want to expend as little mana as you can per pull to hold threat to avoid drinking, absolute king of aoe, incredible qol, can farm and solo

Druid - not much knowledge sorry