No, I disagree. You can totally play a roleplaying game like a "third person", so experimenting making the MC do this or that, create different MCs with different characteristics and play and have fun without having to identify in jack shit.
Maybe, like you suggest, it may be different in another media (where you are more "passive", like tv), but in ropleplaying (video)games it's like I said.
Let's go in order.
1. AVNs are generally not RPGs, and I believe that role-playing in such games is a matter of personal preference and generally not necessary at all. (imo)
2. However, therein lies the problem. Even if you try to play 3rd person in an AVN game (even with a female protagonist!) and be some sort of invisible observer of the MC's fate, it's still very hard to give up ownership of what happens to your character. You can't cut off empathy, compassion, anger, joy, and other feelings and emotions with a knife and just be the "cool unemotional guy from
Equilibrium" from beginning to end.
And that means that one way or another you will react to what happens to your MC, and that's where your true feelings will come to the surface, which you won't be able to drown out with the soothing mantra - "but I'm just an observer", because even while observing and not getting into the character, the player is still worried about what's going on. Because you control him, you are responsible for what he will choose and how he will act.... and that bond cannot be broken on every emotional and mental level. Yeah, like
Maviarab, I don't identify with KaneDom either, because he does act like a chump and even a jerk at times... BUT! He's MY chump and MY jerk!...
and I don't want him humiliated by some leather clad bitch who was lucky enough to be born with a golden spoon up her arse.
You can call it "identification" or whatever you want, but I don't see how it's possible (for me) to sit on two chairs at once, and my deeper self invariably started protesting vigorously even when I was just running a couple of sub-scenes with Kane via Sancho Mod Gallery (to find out more about his real sister). So here I tend to agree with
Maviarab that without a connection to the character (even if only on a subconscious level) you just don't get any enjoyment.