Ok all I going to share some ideas. ok I think the most important upgrade we can make on the C model it’s to pull up the WiFi link and the application. Ok this is what I propose to Costas and all of us her.
On board(ROV) 1Raspberry Pi 4, the 2 motors drivers, 1 battery , the new camera, the batt balance outside of the sphere to recharge without open the sphere. Between the ROV and the surface the Ethernet cable in a floating house and on the shore this Ethernet cable plug in another raspi and on that raspberry on Xbox joystick and one 10” HD screen in a small suitcase. No WiFI no App the good old cable and Hardware. Ok guy’s let me now if you agree. I hope my english is not to bad and you understand what I looking for.

Nice idea! I'm thinking about an upgrade to just move the battery outside the sphere as I'll be using the ROV from a boat in a salt water environment and nervous about having to open the sphere to swap out the battery to often. Maybe also to increase the battery capacity but appreciate any thoughts about this.
I have started developing the python code for this on GitHub now that my senior design has finished.
https://github.com/ArtimisFowl888/Archimedes2/tree/joystick
I have been thinking about a similar upgrade my self except I was just going to use a Logitech joystick and a python script running on a laptop to interface with the ROV instead of an android device and wifi. But I could defiantly see it being done with a raspi and an Xbox gamepad.
I really like this idea. I think using a second pi as a monitor might be a great tool. It has all the ports you need for the ROV tether, a usb hand controller, as we’ll as 3 extra USB ports. Not to mention, this would prevent any WiFi connection problems someone could foreseeabley have while using their android device.
Im curious - are you envisioning setting the pi with the monitor as a router? And do you (or anyone else) have any ideas for what goes inside the hand controller? Since I like to keep this all open source, my mind goes to an Arduino board+PlayStation joysticks.
And thanks for the visualization, I really appreciate the work you put in, and it definitely clarifies your idea.
-Costas
Ok I made this schema to explain what I expect for next upgrade