Problem is that if you want to limit planetary fuel storage, you are opening can of worms. If the fuel storage is limited, should mineral storage and maintenance storage also be limited? And what about missiles. Do you also need planetary magazines to store your missile production?
I wouldn't want to see storage limits on minerals, at least, for micromanagement reasons. MSP and missiles I think could go either way, but the question needs to be asked "does adding this improve the game in any way?" and I'm not sure it does, whereas I can at least see an argument for fuel.
Narratively I think it could be easily rationalized why a colony could store infinite amounts of minerals (and maybe MSP and missiles) but not infinite amounts of fuel simply because fuel is a liquid and therefor needs to be stored in tanks so it doesn't all evaporate or seep into the ground. Ingots of refined minerals can probably just be set in a field somewhere, maybe with a tarp over them in TNEs can corrode, and MSP and missiles probably already have some level of packaging and at most require a fairly basic warehouse.
With the new spoiler race it sounds like the kind of thing that should be held off on for now until we see the emergent gameplay effects of the new race.