Okay, so. I believe that One Man Army should work mostly as it does, but have its description edited to be clearer that it only cares about what other players there are, and only be available on a single character. That way you can have a 'main character' and then a supporting cast, if you're into that kind of thing.
I also agree that there should be some kind of separate level one talent for being a solo character.
And I think that this discussion is pleasant, and hopefully people can continue being civil in it!
I agree. But only up until your first comma in your second sentence. I hope that is a civil way to put it

How One Man Army should work is exactly as its description describes it - not what it does. It should also be renamed to "Lone Wolf"
The bonus should be conditional on the number in your party (AI or real), it should be incompatible with Glass Cannon (which it is) and (here is the difference) it should be available from level 1.
The problem with this is everyone would take it. Then when they wanted to talk to Buddy or the Pigs they would recruit someone, give them pet-pal, have the discussion and then dismiss them again.
The solution to that is to not let people recruit.
"One Man Army" should be renamed "I have no friends" and give extra AP and vitality to anyone who made it to level 8 without actually remembering to use the other useful talents.
In my opinion it makes the game more fun not to wait and store up a point from level 4 so you can have a marginally easier fight at level 8. The last fight is already easy if you are on level 8 before hand in any case - certainly you don't need a few more AP.