yeah Ian is a dick but he is the MC's friend and he's a pretty decent friend at that. the guy's not all bad, there is definite room for improvement. and remember Ian has his own score like the girls. i imagine a lot of things, like his relationships and friendships, will be determined by that and your choices.
You are quite right on this. And given how great the writing is, the scores and various flag events will play a role what will happen. For instance, in my main playthrough my MC has high bromance and Mina scores and the Killian/Mina relationship has not deterioriated (I played as a real friend to them), so I truly doubt the revenge video will be all that "revengy" in this case.
I theorise that with high scores the video will be more a warning shot for Ian, Mina telling him with it to start thinking what he could loose. I point this way because with high scores and being on the specific paths you know that
and Mina knows it too. So I think in this scenario, high relationship scores all around, the video to be hot, but more a "think clearly what you might loose, buster" type.
If the relation scores are low or the MC deliberately torpedoed the Ian/Mina couple, then I think the video will be really a revenge by Mina. And it will be interesting to see how the video comes out, if you have medium scores or were indifferent to the situation.