Read through most of these comments. I think some of my gripes will be fixed in 2.2, but this is what I have so far:
Edit machine settings/custom machine gui (already implemented in 2.2 I think)
Start/end Gcode tab, this could also be implemented in machine settings so the JSON approach would work easily.
Custom material settings gui (Necessity)
I WOULD like to be able to print directly over USB to my kit printer, but it isn't an ultimaker like my other printer.
Why is the temp scaling for layer volume disabled? (I was really excited about this setting, it's why I downloaded 2.1.3 :c)
Profile adding and editing is a little funky (Let us choose a name before it saves?)
Infill angle offset? I don't use this setting much, but for certain models it can be very useful.
Different infill patterns? I thought I had read that different patterns were going to be supported in 2.1.3, but there's no option. Maybe I'm reading what I want to read.
Different color for top layers. The bottom layer is red, but top is left hanging with that yellow. Maybe a green or something would work for that.
Custom supports would be a very nice thing. Sometimes a hoomin knows better than a script.
Most of these are just "nice to have" settings/options, but some make/break use for me, even on the ultimaker 2 I use.
One actual issue I've noticed is that the infill just isn't printing right, seems like it's missing ~20% of what I would expect. I think this issue is also causing some minor nozzle collisions. I'll have to do more fooling around to confirm it, but yeah.
Overall, thanks for your hard work. Last time I tried cura 2, I couldn't even manipulate the model (yes, it was selected). You guys seem to have knocked out quite a few bugs. I'm also happy to report that edge curling is DRASTICALLY reduced compared to cura 15.x . I enjoy that, as it is a big issue in many of the models I print.