I agree that 4 slots leaves pretty much no room for customization. You need a melee warrior, a lockpicker or trap-finder, an offensive caster and a healer. There's not enough room.
Multiclassing to fix holes is also insufficient because the level cap of 10 means that there can be little development of the additional class. It takes three levels for a class to get its specialization.
A party of 4 is not simply a party of 4. You have to count all the summons and pets and all other adds each possible party member can bring to the table. Which can extend the party size to over 8 (if one caster can have both summons and familiar at the same time for example). So the more party members you add to party composition, the more it gets chaotic and lengthly to play battles, because it's turn based and everyone has to play a round.
In that sense, I think a party of 4 is way better than 6, especially as mentioned above for casuals and new players to the genre.
I'm going to disagree with this. Summons - by design - are weak and not the equivalent of full party members. Creating any summoned creatures costs a spell slot, which you can't replenish in combat. It's not like DoS 2 where you could summon freely thanks to the replenishing AP and cooldowns (and additional memory slots).
[quote=Torque]
One could argue it's exactly why a 4 members party is better, because it's more challenging. Not having the holy 6 present in your party goes for more strategic thinking as to which skills are more important than others for the next fight, making it more interesting during camp sessions for players like me who enjoyed a party of 2 in a DOS2 hardcore difficulty campaign.
That's completely and totally backwards. There simply isn't enough variety available with just four slots in the party. This isn't DoS 2 where everyone can spec freely between classes, you are restricted in what you can do.
Stating that 6 slots allows to have all the main different skills from classes and then saying it makes it unique is a complete nonsense. Because it makes every single 6 slots group the same. And so you will always bring the same party no matter the encounter.
You create diversity by forbidding to have all the skills, not by allowing them all. But whatever, as apparently I am off topic.
Again, this is nonsense and completely backwards. It's not having 6 slots available which will make every single group the same: only having 4 slots available will make every single group the same.