After looking over the excellent sheet Cassie made, I'm feeling a little more comfortable introducing content I was concerned might get me yelled at. Unfortunately, my To Do list got bigger because I recognized more areas I'll need to account for. I still need to decide how I'm going to handle submersion and echoes, but the rest is in. I got a decent amount of the Matrix-based stuff in. In the mean time, if you could let me know some nice-to-haves you'd like, let me know so I can take them into account :D
I'm working on it right now and will update you later with how much I've gotten done. I started to waste some time looking into using Typescript, but I'm already using a Pug and SASS build process that might be unfamiliar to most and I don't want to introduce any additional technical hurdles. Add on top trying to figure out the right way to make Roll20 do what I want, and the fact that Roll20 has been going down frequently, and I gotta say it's really hard to stay motivated when I have so many other neat programming projects (and computer games) to work on :( But, I'm sticking to it! Right now I'm primarily focused on getting the HTML stuff working, as I'm going to have a way easier time playing with the JavaScript.
I get to have a design team that works on the layout and workflow, and all I have to do is go over it and make adjustments, then be given the final layout to implement. Recently I've been finding out how spoiled I am at work.