We get lots of ideas suggested, and while it would be nice to provide a long and detailed argument about why we don't want to implement it, that would be wasting a lot of our time which we could be spending coding. There are already 1941 posts in the topic, and this is just one source of ideas we get (there's also other topics, email, Facebook, TeamSpeak, etc.). Usually it's not practical for us to provide more than a short reason for rejecting an idea because there are so many suggestions.
We end up hearing the same ideas over and over, or we hear ideas that are all rejected for similar reasons. We get tired of repeating ourselves so we get lazy and write shorter responses. We could keep some kind of list of suggestions with explanations, but the list would end up being massive and maintaining it would end up wasting a lot of time.
Why do we have an ideas forum? Because we often get really good suggestions here and implement them into the game

But at least 50% (probably more) of the ideas suggested here are never going to be implemented. Even if 90% of the ideas here are rejected we still get the best 10% of ideas implemented into the game, and that's definitely worthwhile.
People get frustrated when we reject their ideas. But imagine if every KaM Remake player (about 50,000 based on number of downloads) suggested an idea and expected us to implement it? Clearly that's not very practical. At the end of the day the KaM Remake is Krom and my project so we decide what direction it goes in and what features get implemented. If anybody wants to fork our open source repository and make their own version of the KaM Remake with their own ideas, they are welcome to.
Please read
my post on the previous page for a description of why we are hesitant to accept ANY new ideas in general, even ones that are not bad (but not great).
Perhaps we need a post in this forum about why ideas are usually rejected (with a list of common/general reasons)?