If a player chooses to skip over a scene, they are clearly okay with not seeing that particular content.
And seriously, would Cassandra's chat have been any different if it was afterwards, and she was clothed?
Yes, absolutely. The chat is about intimacy, comfort, and her personality. Being naked around someone is being vulnerable about them - we see that as a moment of very personal intimacy. Being fully clothed and standing about Skyhold having a chat about each other has a totally different vibe from being naked in the grass, totally alone.
Was ME1's approach silly? It seems to be held of as a poster child of how sex scenes should work.
Cinematically it was OK, though I found it silly because I was thinking about the animators actually having to do all of this stuff.