Ok, the way I see it there are several issues here. NOT the definitions, but the use and response to this issue.
Before beginning I wish it to be clearly understood that I do NOT like such content and can ONLY make comments based on my personal experience.
In my experience the WORST situation seems to be the 'SURPRISE' addition of such content. It is disturbing to play (and enjoy) a game and suddenly have a scene appear that has this content (especially after a long period of development). If a developer CLEARLY indicates that it will happen from the beginning, then SOME issues MIGHT be avoided. This of course depends on the game. If we play for and extended time without this content and it suddenly appears in a way that contradicts all the previous events, then it is a disrupting factor that can cause a problem. On the other hand, if players KNOW that content will eventually be added, and the STORY includes things that indicate it is going to occur then there would be no 'Surprise' and disruption is lessened. Personally, I avoid games with content that I dislike (I'm playing for FUN) and to have a sudden disruption to my enjoyment often means an END to my playing (this is NOT limited to adult games).
The BEST way of dealing with bringing in content that MIGHT be an issue that I have seen/experienced was in the Game 'Midlife Crisis'. The Creator took the time to create MULTPLE versions of a scene and gave CLEARLY marked choices of what would happen based on the players choices. The players could see what each choice would include and decide what they wanted to see or avoid. THIS is an example of including a variety of content while avoiding the WORST of the problems. Unfortunately, this DOES increase the time required to develop the game. This can also reduce problems with the 'Surprise' factor. If the content is able to be avoided in this way MANY will simply play what they enjoy and ignore that the other options even exist.
As stated above the 'Surprise' situation of including content (NOT limited to NTR) is perhaps the WORST. If a game suddenly presents a situation that does not fit with all that has happened before then it causes disruption and serious problems. A NON-NTR example might be urination. If a game has never had that content or any discussion of it, then to suddenly have a scene appear with this does NOT fit and will cause issues for players REGARDLESS of their feelings about the BASE 'kink'. For those that dislike what has happened there is disappointment (possibly anger) and often the result is abandoning a game. Fans of the 'kink' may wonder why it has appeared so suddenly and might be confused as to the purpose. There may ALSO be concern about what other new events might be included later that are disliked and players on either side might, again. abandon the game.
A second (and just as serious) issue when discussing NTR content is the problem (on both sides) of people who appear to request (demand) that a game be changed to fit their personal desires. MANY times, I have seen discussions of a game be DESTROYED by the appearance of someone talking about how much BETTER a game would be if something (NTR) was included. As I said I AVOID this content so do NOT know if people go into discussions about games that include it and request (demand) it's removal, but doubt it happens anywhere near the same frequency. In part this can be reduced with CLEAR information about what a game will include. Of course, this is NOT a guarantee, as I have encountered (IDIOTS) people that demand NTR in games where the creator has declared from the beginning that they HATE the content, and it will NEVER be included. Sadly, there are people (IDIOTS) that just want to cause problems and watch everything be destroyed for 'fun'.
Yes, I am (somewhat) guilty of making requests for content to be included. THANKFULLY, people seem to understand that I am (MOSTLY) being silly and trying to get people to LAUGH. Yes, I do like to bring up Chocolate Chip Cookies (Tiny Tina is a GODDESS), and several creators have added humorous scenes playing with my requests. Perhaps the most entertaining situation was with the second chapter of 'TIMESTAMPS' where the developers added a 'Moose and maybe a Squirrell' to the introduction because of my silly comments about the first chapter. For those who wish to experience this you need to name your MC 'Moose' or 'Shiva' (I don't remember which at the moment). I have added this section to show that I am willing to accept my own (silly) guilt.
The last thing I wish to include here is the DIFFICULT issue (debate) as to whether LESBIAN content in a MALE MC game should be considered NTR. I am unsure about this as I CAN see a situation where I would consider it to be a problem. As an example, let's consider a scene where the MC (player) sees two ladies having (SEXY) fun. Depending on what occurs in the scene it may or may NOT be the NASTY three letters. The situation is difficult because there are MANY factors to be considered. Are both ladies Love interests?? Has the MC previously accepted/declared their desire for such events?? Is one of the ladies a rival for the MC?? Is the MC invited to join?? These and other things must be considered before we can say yes or no in answer to the question of what is happening. From my experience MOST developers seem to consider these situations to be a way to expand their story and the issue of NTR does NOT arise. I CAN see that problems could be created, so I am unsure if any single answer really works for these events. Sorry thinking about this is making my head hurt.
Well, I'm done with this topic for now. I'll be interested to see the thoughts of others on this topic and HOPE that people will avoid the NASTY fights that can occur when discussing this topic.
Oh,
@SeveredRealms you are CRUEL for MAKING me create this wall of text. Because you did this, I DEMAND that you add Chocolate Chip Cookies to your game.
Just some thoughts.