Expedition: general discussions.

3. CHECKS. CHECKS. CHECKS.
Either learn to wield a sword or learn to use your words, otherwise, you're useless.

Here are my thoughts on this.
1. The guy has a lot of intelligence, but little charisma. Is he an autist who can't put two words together? Why not give him a bonus to persuasion based on his intelligence?
2. The character is a mountain of muscle with a lot of strength. Why not introduce an intimidation option and give a bonus for that strength?
3. The character has a lot of perception. Okay, why not give him a perception check to notice some peculiarity of the person he's talking to, maybe even the ability to better guess their thoughts and mood, and again, use this in the dialogue?
If everything is structured this way, then charisma is not needed, only for leadership skills and possibly trading. Although, there is another side to this, you can explore using charisma in combat situations, as you did with the Camelots, or as in Pathfinder, where charisma turns out to be needed for some priests.
And all this does not prevent introducing separate skills/perks for more effective persuasion, charm, etc., I suppose?