There is no incentive really, beyond the temptation to become a really fat ship. With your limitations neither will it succeed in being able to properly defend itself or for that matter garner useful resources. I could see it being a good idea with the right content but frankly I dont think it will happen. As another said if it has to do with power such as equipping base gear it would either be to powerful or useless. Unless of course you were to say not allow the ship to equip weapons (base missile launchers and aura generators) and allow it to equip higher levels of other base gear and maybe an aug or two. Thats barely incentive though, it needs a purpose... It could be that giving it some role in setting colonies up, as in a base that can dock at a base... if that is possible. Not sure I really like that idea but, it could also be some type of temporary attachment base that can latch on and off of planets at will (or within set boundaries?) Which base on your class will have different effects on the planet. ExE would have the usual, great extraction... CA, over a period of time could heal ever so slightly, but naturally, the planet (say those planets under 20 base suit if that still means what it use to mean) StM could temporarily provide bonuses to otherwise vulnerable bases (only while attached to the same planet)... and I guess... just dont use one on your MFM Iunno I CBA
TL:DR it would be a nightmare to code anyways.