I don't take requests because as soon as I start, I will suddenly find myself inundated with requests from everyone, and there will be hurt feelings if I fulfill some but not others. To avoid this, I have a blanket “no requests” policy.
As for not accepting ideas or suggestions, the main reason is because I have plenty enough of my own that I don't need more. I watch Forgotten Weapons and Firearms Expert Reacts, I play other video games, so chances are that whatever you want to suggest is something I've already thought about and either didn't find it interesting enough to pursue or couldn't find a way to make it work in the engine.
Additionally, there is a chance that whatever you want to suggest is something that I'm already working on, in which case it might look to an outside observer like I'm fulfilling your request once I release it. This could lead to the aforementioned hurt feelings if someone thinks I'm taking your requests but not theirs. So again, to avoid this, I have a blanket “no ideas or suggestions” policy.
Burnout is a very real danger for all creatives, and as such, sometimes I'll abandon a project for months or years because I'm tired of working on it. The last thing I want in times like this is people badgering me, wanting to know when the mod will be released. To prevent this possibility, I only ever announce/showcase things that I've already completed, or which are mostly functional but lacking polish.
As attention spans grow ever shorter, I fully understand that video tutorials which “get to the point” faster are more popular. However, the danger in this approach is that viewers can fall into the trap of blindly following along, only to reach the end without retaining any of the knowledge of the steps it took to get there. When making tutorial videos, I always try to explain why I'm doing something, and not just how, so that viewers will hopefully retain the knowledge and have a better understanding of the theory, which should help out when confronted with situations that aren't explicitly covered in the video.
Also, I don't like to skip over the small details because whenever I have to look up a tutorial, it's usually because I'm a complete beginner with no prior knowledge, and can't figure out how to do something simple. It's incredibly frustrating when the host glosses over it because they think, “everyone should already know how to do this so I won't bore you with it.” No! That was the part I needed help with! So, when making my own tutorials, I try not to skip any steps, no matter how small or insignificant, so that viewers can follow along in as close to real-time as possible.