I’m playing as a Warlord (Soldier + Oathkeeper) now, which requires the second expansion. I think you said you only have the first expansion? I think most people with the first expansion only would probably go with a Death Knight (Soldier + Necromancer).
The second expansion has a Sword and board character class called the Oathkeeper. Not only do you get tons of skills with a bonus if you have a shield, it also has good Area of Effect spells like you want. There’s one called Judgement that’s very satisfying. Everybody gets pulled toward you, so you act like a giant magnet when you activate it and enemies stumble and fall towards you.
If you don’t have the expansion, the Soldier does have a couple of AoE skills, one is Blitz, where you rush toward an opponent, and when you make an impact, I believe the resulting impact has a radius, so enemies clustered close get hit. It has a 180 degree arc effect in front of you. There’s another skill, Blade Arc, that also hits 180 degree arc in front of you, and finally there’s a Force Wave, which sends out a wave directly in front of you that can briefly stun enemies, which is very nice for some crowd control.
If you do go with the Necromancer as your second class and stay away from pets like skeletons and blight fiends, you’ll have some nice aura effects that will enhance your damage and weaken enemies, and you eventually can get something called Siphon Souls, which is a nice area of effect damage spell.