I guess I should explain that comment. I don't see how the typist cannot effect your IC interactions. As much as you may not want to admit it, you control your character. Your motivations WILL have some effect on the character. It cannot be helped.
I think so, yes. Perfect seperation between character and player isn't possible. After all, even when you play someone that is completely different from yourself (even when it is a raving psychopath), the character still 'comes' from within you, your imagination. On the other hand, it isn't that hard to achieve a healthy amount of IC and OOC seperation between player and character. And that is a good thing. Especially if that character happens to be a raving psychopath.
It really IS quite important to seperate IC and OOC in many significant ways. I don't think it is a matter of 'preference', really. It is a requirement for RP-ing like adults. Many get angry at a player because his/her character isn't behaving nicely to their character and they fail to seperate IC and OOC. And that creates a lot of the most stupid disagreements in SL. You can only have decent 'adversaries' in RP if you can make the distinction, when you see the difference between author and character.
Not saying that you don't. But if this goes from character to player, it also goes from player to character, technically. If I dislike George R. Marin, that doesn't mean I have to dislike Tyron Lancaster, his character.