An opinion is: A view, judgment, or appraisal formed in the mind about a particular matter. Or; a thought or belief about something or someone.
Someone wanting to see content in a game, is a viewpoint, something that they've determined in their mind about the game, a thought or belief that they've had, that it should be there. Something that they think or feel would make the game better, something that they would want to pay for.
Example: I think this game should remove all NTR heavy content because that's not the focus of this game, it's better off with the lighter NTR elements, and it's nice to see something where only girl on girl NTR could happen because there's not much of that out there.
^This is an opinion.
Example: I think this game should have more NTR heavy content because the game introduced the concept of this sex cult with slaves and stuff, so it makes sense that you should be able to experience some of that if you want to. Imagine if you could push your interests into having threesomes or into more debauched scenarios, really open up the fetish content in the game, I'd love to see something like that.
^This is also an opinion.