intellect as a required stat would be solvable with a few changes:
1) allow lucky looter to apply a bonus to quantity of ammo found
2) allow the barter perks to modify the ammo available at a trader, or add some modifiers that make it give traders more consistently available and more numerous amounts of ammo
3) make vehicles purchasable from traders and/or quest rewards
This is the big one:
4) move better barter, daring adventurer, and charismatic nature. Potentially to a new charisma stat (it obviously won't be as big or necessary as intelligence, but it could be made only 5 points and very cheap to buy, since making people invest just as many points into a new stat utterly defeats the purpose), but you could also make them not under ANY attribute...they just take points to increase
This solves the issues of:
1) getting decent gear - more applicable trader tools/weapons, and easier access to quest rewards by being able to get better barter and daring adventurer
2) ammo - being unable to craft ammo will eventually leave your magazines empty. Access to more found and bought ammo helps offset this.
3) transportation - vehicles are the biggest thing exclusive to intelligence only. Allowing vehicles to be purchasable or earnable from traders (at extreme prices and maybe level 4/5 quests only) gives a no-intelligence player access, but not choice or consistency in obtaining one.
most people will still use intelligence, but this would allow people to CHOOSE to play without feeling like an attribute was required, which i feel is important to the "RPG" aspect of the game. It's clearly trying to push a "choice" aspect, so I feel that no attribute should be REQUIRED, and you should be able to play a reasonable (hard, maybe, but at least consistently possible) game without [insert any ONE attribute here].