You don't need to have a Ranger or a Rogue, what is something very basic in this game is to have at least one character focusing on each of the 3 basic stats which are Strength, Finesse and Intelligence. A Ranger/Rogue would be focusing on Finesse. That's what I recommend, have at least someone focusing on Finesse. This goes beyond combat, there will be events where you'll need a high Strength/Finesse/Intelligence. But if we talk exclusively about combat, you can do well with any party combination.

This is the party composition that I recommend:
1 Strength based character (Warrior), 2 Finesse based characters (Ranger and Rogue), and 1 Intelligence based character (Mage)
I wrote a lot about it if you're interested: http://forums.larian.com/ubbthreads.php?ubb=showflat&Number=665003&page=1

Just a reminder: my recommendations are not based on optimization for combat, like the recommendations made by DrunkPunk. My recommendation is what I call the "archetypal party" for DOS II.

Last edited by Wilker; 04/08/20 10:04 PM.