The only other thing affected by charisma is your companion's nerve, which really isn't that important. Even with a starting value of one, it isn't hard to increase your speech or barter to a acceptable level. Charisma is 1 because it is the most useless stat in my opinion. You can choose to get an implant for each of your SPECIAL stats, or you can ignore charisma and/or endurance in favor of the increased DT and health regen. Endurance is also at 7 for implant reasons. Add any hat with +1 perception and an implant, and you've got yourself a perfect 10. Also, with the four eyes trait your perception will be 6 without glasses, and 8 with.
Perception is at 7 because it is one of the determining factors of your energy weapon skill.