No. Secret aid would be a terrible idea. Yea, sure, it would hurt the NPO because guerrilla groups could be funded. But it would make large alliances no longer accountable for their actions. Why fight a costly war yourself when you can fund proxy wars with no one knowing? Helping the little guy does not help a game! It has to be balanced. For instance, tech scarcity is great, because how cheap tech is for young nations is balanced by old nations desire for it. Forcing alliances to be held accountable (like having trading public) keeps inter-alliance conflicts real, and game changing.
Furthermore, enemies need to be able to be crushed. Trust me, use NS as an example, if war has no meaning, things cant change, and change is what your after. Once again, just trying to overthrow the NPO is not really what your looking for, and beware to not use long term harmful practices to achieve short term goals
I do like the idea of limited land. Wars are usually fought out of desire for limited resources. Hence, most of conflicts have roots in senate seats. Currently, land is an unlimited resource. What if land were treated like senate seats or tech? Just limiting land would simply give another advantage to big alliances. What if land got more and more expensive, not by the more you bought, but by how much land was owned in a color sphere total, would give small alliances in empty spheres lots of easy growth, while making larger dense alliance need to push out for more room.