You can snap to begin/end of sections using the , and . hotkeys.
Once you do that, you can also use the bracket hotkeys [ and ] to set the start and end of the playback range.
I believe we just recently fixed trim left and trim right and those fixes will be coming out in 4.20.
All of your suggestions seem reasonable. It’s just a matter of resources and priorities. We’ll try to incorporate some of your suggestions in future releases.