I agree that a 1:1 approach feels best for the player/game.
I feel the base should be 10 to be in line with all of the other starting attributes, although if it were to be 5 I don't think it would negatively affect anyone.
From a back end, if 10 is the base and it is a 1:1 system, it could just have the base be 5 behind the scenes and add 5 for the player. (Calculate base 5 display base 10)
But all that is semantics if the general agreement is a 1:1
