I am doing my first run trough the game and I'm trying to do it with pure class only. I've made a custon paladin as the main character and plan to go with a Fighter Lae'zel, a Thief Astarion and a cleric Shadowheart. So sadly, it won't have any spot left for an offencive caster. Will it gimp my team to much ?
I also started off thinking that I must have a Tank, Healer, Thief and Arcane Caster. But the game is easy enough that you don't need to fill all those slots. As already said, Clerics in 5ed/BG3 have some AoE spells and your Goth Princess can fill that need, although you can complete the game without such spells. Heck, you have blackpowder grenades ...