About the main topic of the thread, honestly I would like to make a case against this change, or at least have there be an option to turn it off. I think this change is very interesting and experimentative, which is definitely something I love the app doing.
However, I don't think having this as the default is a very good idea. The only reason I've read so far for this change would be for hatching, and I do think it improves the line tool's practicality for it, but is it enough to justify fundamentally changing the line mode as a whole? I'm not so sure.
Mattnava provided examples of traditional work using crosshatching, but I don't really understand what any of those drawings have to do with the line tool. In my opinion those examples would be a good case against this change, as they are done with a pen/pencil, which is the equivalent of freehand. To be frank, I don't think anyone should use the line tool for cross hatching. I don't crosshatch or use it in my work very much, but to me using only straight lines leads to a very rigid effect when using it to shade rounded form, as cross contour lines are rarely ever straight. I could see it being used for a stylized effect, or rendering flat objects, but I don't think this justifies changing the line tool fundamentally. I think you would have a great deal of trouble finding an example of a drawing crosshatched using the line tool.
So why not change it? Let me reiterate really quick that I'm not advocating for the removal this change, but rather having it as an option, and not the default. I don't think there's anything too fundamentally wrong with this addition, I think it's great as my philosophy is the more features the merrier.
The first reason is that to my knowledge every other software doesn't have this function, and use hard lines as the default. I know this isn't the best reason, but I think a feeling of familiarity when using a new app is essential.
The second reason is that if this is the only option, it removes the ability of creating those consistent hard lines without changing brush settings which is very inconvenient.
I hope it is understood that I don't mean anything personal, and don't really have any stake in this but I just figured I would give my two cents about this change. Thank you!