I just glanced over the (interesting) article. It seems to compare mostly to a solid Dyson sphere as the megastructure, which does have a number of drawbacks. However, many of those can be overcome by a non-solid Dyson object, like a swarm. And by separating energy collection from habitable space, i.e. by using literal, dedicated habitats.

The idea of moving planets around is new to me, and I’m sceptical of it. How much should we worry about impacts on orbital mechanics? I heard many planets are in kind of synchronized orbits and wonder how a significant disturbance could ultimately affect Earth’s orbit.

From watching many Isaac Arthur shows, I got the impression that practically any location can house impressive number of people, if only enough energy is provided. This includes existing bodies like planets, moons and even asteroids, but also empty space around Earth or further out in space, even outside of our solar system. The energy could be provided by a central Dyson swarm or decentral nuclear/fusion reactors.

I guess it is easier to take many small steps than to make on big leap. So wouldn’t it be better to build various habitats, colonize a number of smaller objects, than to move giant planets around? And how would the energy/material requirements for these endeavours compare?

If all this was only about ourselves, there would be little reason to think so hard about a so distant future. The current-day value of these ideas is probably to inform our search for other civilizations. The better we can guess how they might live, the better we know what to look out for.