Either or both. An issue on Gitlab with a link to a Forum thread is common.
There are actually several different types of thing in your suggestions.
The last one is the web app user interface, which is very easy to change when changes are agreed. There is already an issue on more buttons in the web app #241.
Camera stream resolution and extracting just blue are deep in the camera control, I know nothing about how hard they might be.
Supporting the other Pi cameras is already in the pipeline, @r.w.bowman is making progress on the software and has the main parts working I believe. The hardware modifications for pi camera module 3 are ready to go. The HQ camera is similarly simple if we crop to the centre of the sensor. This still has plenty of pixels to cover the optical resolution I think. Using all of the bigger sensor is difficult to achieve without a very long optics module (on another thread here - Support for HQ Pi camera).