Imperial upgrades

It seems odd to me that once a system is included in my empire I just leave it hanging there, not doing jack squat about it. A well-developed system would contribute more to my strength that an ill-developed one, and wastefulness is certainly not a fitting quality for an invasive inter-universal species. Therefore, it makes sense that I ought to be able to pour wealth into my colonies so as to develop them and derive better use from them.

In all likelyhood it'll be a better idea to invest in each aspect of a system separately, upgrading it's force, wealth, science and possibly also land, than to simply throw money at it and get specks in all aspects but nothing significant in either one. Might be a good idea to have a requirement of having a provost king assigned to a system for it to be upgraded.

Also, to the best of my understanding trade ought to be a mutually profitable endeavor unless it's simply a covert way of sapping more of a system's wealth than occupation. If I'm correct and connected systems are part of a legitimate trade network then their wealth should increase from it. The greater the number of systems in the network, the greater the bonus.

EDIT: one more thing. Are my people the only ones with ovservation technologies? Currently the other systems don't even have an observation graph, which seems quite odd to me. If they're wealthy, curious and not completely stupid they'll build telescopes of their own. And if they have such tech, then included systems ought to consolidate vision into my empire. Worst case scenario, positioning my telescopes onto different points in space ought to give a boost similar to what I get in terms of science just from knowing about other species.