In short: we have been building character traits for the MCs with our choices and now we have to live with the consequences. A Chad Ian will be confrontational while the more laidback “original” Ian, as you put it, will try to talk his way out of his problems.
I know that can be even frustrating at some points (“but, but… In my mind MY Ian wouldn't have said that''), but the sad fact is the game can’t read our minds, heh, it can only read the variables WE HAVE CHOSEN through our decisions.
I think the player impression is different though, because the whole Ian/Lena + Holly thing is directed at Ian himself, the other main character (and the one a majority of the player base probably identifies with, being male, you could theorise).
With Ian, many of the exchanges that shows a difference in approach is geared towards secondary characters, which is what my impression is, is part of the criticism of the mentioned Ian/Lena confrontation.
Mostly his variation comes through how he confronts Robert/Milo, how Perry comments on his exploits with women, and his interactions when going out.
Frustratingly however,
Emma mentions Ian's attraction towards Lena regardless of what's going on between them. In my playthrough Lena and Ian are nothing more than friends (even though their agenda bar shows
) but
Emma still talks about them as if Ian is head over heels for her. Lena just says that she' exaggerating.
I really do hope that Eva will have some consideration for us non-Ian/Lena shippers in some of the variables. I don't mind so much that the early game assumes the interest, it's part of the story after all, but it becomes frustrating when the NPC's keep inferring and implying interest where there never was any expressed.