Hi. I am really a fan of the diverse KDE software and rely on kdeconnect heavily, too.

I would like to see a small enchancement on kdeconnect from client side - a (opt-in) visual feedback feature that confirms a command was sent successfully to host device (for e.x. being sure that I locked my laptop from my android device).
I would like this feature to be enabled both globally and per-command. Per-command would likely work as an override for global setting. 
Lets say you are in another room, want to lock your laptop, you press your command, but you are not sure if it worked (say wifi signal is not strong). This, I think, is quite a good feature to have.

Expanding on that, kdeconnect also could also react to bash exit return codes (process returned 0, for example), which would be a different beast to implement on its own. This could also be customizeable on return codes - for example, code 0 would get a notification with customized string, then code 1 with its own string, etc. 
This particular request is, of course, low priority because its quite a niche feature.

I hope I made this understandable, if any questions arise, I will gladly respond.