Nanogel: Economy & Logistics at Unlimited Scale

I think the question is posed from the wrong view point.
Sure, in a 10vs1 planetary situation the attacker should be able to successfully attack that one planet, but just because that also should work (even if it is a bit harder) with just one planet attacking the other planet, given a good strategy and a bit of preparation.
The real question should be:
Should the attack of one planet feel like attacking 10 planets if the defending player has the resources of 9 other planets at his disposal?

I for one think that's not a good idea. That is one reason why I'm against global economy (at least on interplanetary level), it would probably lead to turteling on a planetary scale.

That depends on how we do planetary assaults.

It does the opposite. A sector wide economy means that money gets spent where it is most useful. Typically, this is on the front line, where it can do the most damage to the enemy. A local economy means that every planet is constantly building stuff, perhaps hours after it has been conquered. Units and defenses pile up with no end in sight, and an invader has an incredibly tough time calling in reinforcements. Local resources == turtle fest.

There's no way to hide metal production. You have to spread out to capture the most metal possible. However, energy can be hidden in such a way that it stops being a meaningful target. If it connects across a sector, then players will hide generators on their best defended worlds, and never fear an energy shortage. That's no good.

It would be better if generators had to be in some kind of proximity to the things they support. That forces generators to be spread out just like metal (even if it's only tracked per planet), so they can remain a point of weakness in direct battle. Exploding generators further encourage base sprawl (the singularity gen in ZK went nuclear), so that they won't chain react and wipe out entire bases.

I can think of 3 things for this:

1) Like in SupCom, adjacency bonuses, though unlike in supcom allow up to 1-3 squares of empty space between the generator and the structure you want to give adjacency bonuses to. This way you can still have some room to move units through, and not potentially block production exits like in SupCom. Just make sure there is a limit count on the number of adjacency attachments a structure can have.

2) Power Grid taken literally, many structures are unable to function effectively without having generators nearby while others are unable to function at all. Like the Starcraft series Protoss for example.

3) Greater use of natural terrain induced power generation. SupCom had Hydrometal Power Plants (iirc) which were powerful for T1 but useless by T2. PA could have a greater focus on similar power types by providing more natural power generation terrain types that encourage players to build on natural high power spots. Much like Gas Giants are planned to be a major power source in the game.

Could also make it so that only basic power generation can be built anywhere, while advanced power generation requires some type of natural terrain energy hotspot.

I agree that the resource system should be base localized (but I wouldn't convert them into 1 resource). In fact, I would make all energy and mass local to the base and would have you set up how much of produced resources gets diverted to other bases/planets . The problem with this is that it might make the economy a bit micro intensive. One solution to this is making an economy planet-local but somehow I feel this concept does not go together with the constant economy flow that was present in TA/SupCom.

That would imply, that that one planet has the build power to suck up all the resources produced by 10 planets. If that is the case, why shouldn't he be able to output all of that? After all it should take some serious effort to get that much build power in place.
Also, you shouldn't attack the one planet which produces everything. Attack one of the other 9 planets, since those provide the fuel which keeps the production going. Since there is way less unit production on those planets and it takes time before the reinforcements from the production planet arrive, taking them out should be quite simple.

Build power already is localized, I don't really see, what making it be able to run out does accomplish, besides annoying players and slowing everything down.