I think your initial assumptions, and your final comments, are spot on. Maybe I just don't understand the physics of mass vs. weight in space, but imho, if your thrusters are rated for twice your mass, you should be limited to landing and taking off from 2g or slightly less planets. For ships where the thrusters are only rated slightly above the mass of the ship, there are still billions of planets and moons with a gravity of 1g or less to land on. I don't know why Frontier chose to do what they did, but it was a bad decision. Higher G planets could possibly be landed on by specialized landing craft which they could introduce, but there is still the problem that people can't survive in high G environments for more than a short time. Even that could have been overcome by using remotes.
IMO, thruster vs. G limitations, landing craft, remotes, and etc. would have added a lot of depth and interesting game play, but Frontier again goes for just a thin crust, and it's a shame for all of us.
Nice vid, btw.

***edit***
I have a question though. Are you using analog thrusters - not just buttons? I assume you must be, or maybe you can get away with digital thrusters with a small ship. But heavier ships do behave differently on high g planets. I don't think you could have taken off like you did if you were in an Anaconda - I think you would have crashed back to the surface. And if you were using digital thrusters with an Anaconda, I think one press would have sent you crashing down. But I haven't tried a high g planet in months, and maybe some things have changed with patches.