The complexities of all of the options are so great, that checkboxes are too simplistic to address most people's needs. I voted "important" in principal based on the concept of needing an easy easy way to specify edge conditions (a wish posted elsewhere, too).
A checkbox would just be to turn the options on and off. Checkbox for a gutter, checkbox for fascias, etc. Once it's turned on, then the user could customize each. A different 3d program that I had been working in automatically made the fascia, gutter, and soffit for it's roof tool. For example, when I drew the roof with the manual tool, it made a 12" overhang based on pre-set settings, it placed a gutter (which could be turned off with a checkbox), and it placed the fascia based on pre-set figures. In Archicad, I'm having to go through a lot more steps on the roof tool to get the same things done that were automatic in the other program. The other program, however, could not do custom guttering or fascias. Unless I'm doing it wrong, right now I'm having to draw a slab for the fascia and trim back the roofs to meet the fascia. For instance, when I make a roof that 9 1/4" (for 2x10's), it makes a very large fascia area. I make a 5 1/2" deep slab (for a 1x6 fascia), and trim the roof back. Having the options that I recommended would speed things up a lot!
id rather time wasnt expended adding a feature like this which ultimately would find of limited use due to the multitude of options which probably wouldnt be addressed. A dedicated addon might work though. I personally use a library part which works quite well but obviously doesnt update along with a roof.
John Hyland : ARINA : www.arina.biz
User ver 4 to 12 - Jumped to v22 - so many options and settings!!!
OSX 10.15.6 [Catalina] : Archicad 22 : 15" MacBook Pro 2019 [/size]
I honestly think it would be more productive to make the Profiler and SOE tools more robust. You could then produce elaborate gutters, fascias etc. and scribe them to the roof pitch as required. Tilt the profile and cut - wham!
Though to be fair, I don't even use the roof tool much as most of my projects are high-rise flat roofed buildings. Though a good profile tool and better SOE would be a boon - create a wacky profile for whatever, tilt and cut - wham!