This is a perennial question, but I was wondering if anyone ever tried to concisely say what bases needed to be covered in a D&D party. 4th edition had the system of striker, controller, leader (support really), and defender, but since then it seems somewhat unclear. We have the sense a party of 3 sorcerers and 2 wizards would be unbalanced, but apart from that...? Seems like it would make it easier for, say, a player joining an existing group of 4 to know what the party needed, for instance.
Here's how I evaluate party make up for combat
Combat
- Frontline (Tank/Damage)
- Ranged (Damage)
- Control
- Healing (including temp hp generation and party damage reduction
- Party Save Boosting (Bless/Paladin Aura/Artificer Flash Of Genius)
- Counterspell + Dispel Magic
My goal is have as much overlap in these areas as possible. So if there is a party of 4. Ideally 3 characters can perform each of those roles but i'd settle for 1-2.
Non-Combat
It's really about having as many of the skills as possible covered with some utility magic like fly/teleport/invisibility/pass without trace/etc.
Example
Party has a Paladin, Cleric and Druid. What would be good characters to bring along
Paladin and Cleric can both function as front line. Druid can add summons to assist. Front line feels covered
Only Cleric and Druid have any range and their range is small. Ranged is lacking
Control. Druids are strong at control (entangle, plant growth, etc). Paladin depending on subclass might have a bit (thinking conquest paladin). Cleric has a dab of control capabilities.
Healing. The whole party can heal.
Save Boosting. The Paladin and Cleric can both grant saves. (Bless and Paladin Aura).
Counterspell + Dispel Magic. Dispel Magic is covered with the Cleric and Druid but there is no counterspelling.
I would find a character that can counterspell and does solid ranged damage. I would probably lean toward an int character since str, wis and cha stats are covered. IMO, best party member for this group would be a damage focused wizard with counterspell.
If I wasn't going to bring a wizard i'd next look into sorcerer/warlock. For a distant third I'd look into a dex archer character (Fighter/Rogue/Ranger).