So, a playable Cookie Monster Devourer Golem?
A problem I see with this is why does the AI get more upset than usual if you nuke a planet instead of capturing it, but doesn't throw a giant fit with you having a Planetcracker as a primary ship? If I were the AI, I'd be less scared of a nuke than a giant ship that consumes entire planets for everything valuable.
Oh, and I, as a human, rather like being on a planet rather than in an artificial space habitat.
The multiplayer aspect of it doesn't sound great to me. Why pay my buddy to protect me when I can just take the planets on my own, field a massive Spire fleet, and go toe-to-toe with the AI? Early game, it could be helpful. But as time progresses, these nomads become less effective due to a normal player being able to field a lot of ships, different types of ships, and make bottleneck planets that the AI loves to suicide jump into. Also, nomads would be reliant on a fleet. How can they really take on an Exo wave? When I go against those in AIWC, I like to hide behind a bunch of planets filled with turrets to keep me safe. Now, you're probably saying the fleet ships would be buffed. The only way I could see that working is if they were MASSIVELY buffed. As in, nearly to the point of a Spire fleet. Otherwise, you'll get wiped out and have no way to rebuild since you would have to take a planet to gain resources, but you need a fleet for that, which the Exo just wiped out.
Why not just bring back Champions? Then you get the niche back, with fewer problems on the surface.
All that being said, it seems like a cool idea to me, so if the issues are solved, I'd be on board.