Personally, for the Expert mode, I used Rogue-Rogue-Barbarian-Cleric. As for skill points, I pumped damage into the physicals and Intellect into the Cleric. The 2 Rogues and Barbarian got 3 strength a level and Cleric 3 intellect.
In the first couple of levels, the setup may become difficult but once you start getting gear, it makes the game simple.
I stacked Speed gear into my physicals and Intellect into the Cleric. The Speed gear pretty much assured that when the fight starts, 2-4 of the enemies will already be dead.
The bars I ran for my team were:
Rogue:
Attack-Sneak Attack-Pierce Defenses
Sap Strength-Create Opening-Cripple
For this bar, Sap Strength is used more on legendary bosses to prevent their damage potential. Cripple is there to debuff a legendary boss before it gets a turn. Create Opening is simple enough. Sneak Attack is to get rid of pesky enemies.
Also, with this bar, I ran 25 Poisoncraft which becomes an easy crutch later on however I did not max out Elusiveness. Maxing out Elusiveness would relay a lot of damage to the Barbarian and might be suicide.
You place the rogues in the front left and front right.
Barbarian:
Attack-Whirlwind-Charge
Dismember-Pulverize
As you may have noticed, the bar only has 5 skills because that's all that you really need. You could throw in Jostle if you fight the Minotaur boss but it's usually not that important.
Whirlwind is massive AoE, Charge is massive damage against a single target, Dismember prevents damage, and Pulverize makes bosses easier to kill.
You place the Barbarian in the front middle.
Cleric:
Attack-Heal-Smite
Heal All-Revive-Holy Light
The only skill I think I'd have to explain is Holy Light. This skill is a nice debuff as well as a nice finisher for Undead enemies.
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As for what the best gear is for classes, I found the Cloak of Flames to be amazing for a Barbarian. This is due to the strength, endurance, damage reflection, and quickness bonus it offers. With full speed gear, you can easily achieve 100-115 speed.
For the rogues, I found Distracting Blades to be the best off-hands due to the +hit factor. This makes blinding the rogues futile to an extent.
For the cleric, I used Runed/Vampiric Maces of Speed and Runed/Vampiric Censers of Speed.