As for open world world checks only needing one Int character? Same could be said for Wisdom and definitely could be said for Charisma. Having more than one character who has a decent Arcana score means you get multiple people rolling dice, which dramatically increases your odds of making the check. Same goes for Perception.
In open world Int\Wis\Cha are pretty similar with exception that perception comes up WAY more often than others and in normal dnd games Cha is not that bad scince sometimes you have to split the party to gather info in short amount of time, here we have our game limitations, but my point was for player character. You will be talking with companions all the time, persuation will come up quite often regardless if you have other char as party face. Wis is diffirent because there are tons of spells that target Wis, dumping it hurts every character that is going to fight somthing with spells at some point. As i said, so far you dont have anything important that comes up with int, Cha at least helps you with companions.
