I can relate with you with the wanting to improve, but not improving fast enough. And I 100% lose my patience really fast, because often I just feel like I haven't improved at all. Sometimes I feel like I did a fluke that looks good and I can't replicate it anymore in the future, it feels like I've gotten worse. It's all in my head, but I can't shake the negative feeling off.
ONE is amazing and I'm pretty jealous of him. I'm pretty sure he's fairly decent with his art, but he just intentionally doesn't as much effort in it as he could have and his manga is so nice.
I actually have some experience and knowledge with Paneling, Narrative techniques, etc. (Scott McCloud's book or PDF files talks so in depth about it and it's lovely), but I haven't really been practicing it at all. I probably should start doing some comics, even if it looks horrible. Cinematography is something I'm somewhat practicing, so I at least have that. I'm not really passionate about these subjects, but I do look into them and try to understand them. I probably would want to try and write stories aside from Visual Art, since I can later on apply it and make a VN or Comic out of it. I don't know why, but I feel like I need to get good with basic art first before I do that, while I know that it's better to practice a few multiple things at once, instead of just solely 1 thing. I'm not really good at writing either, so that's probably why.
As for the Visual Novel, overall I did think the pacing was pretty good. I do agree with you there are slow parts. I do have my criticisms, but I decided to not start, since I won't be able to stop and it'll end up being a huge wall of text hahaha.