Deployments and Reserves

Ever since I made the decision to put ships into reserves when they are built, I've been gnawing on one problem: Balanced deploying of ships.

I don't want players to be able to deploy ships anywhere they want, because they could deploy in middle of an enemy terrority, making defense impossible.

On the other hand, I don't want players to be restricted to one central production center where all ships originate.

Then there's the problem of sending ships back into reserve. I don't want the MoO 3's approach where you can disband a taskforce anywhere, and it's back in your reserves after 5 turns. I've used this to recall ships from opposite edge of galaxy because that was faster than having them travel back.

So what to do? I do like the idea of building mobilization centers, but the problem with mobilization centers are that they're one price, and with my empire-wide production, it'd be easy to just conquer one system, then have your massive empire build a mobilization center at that system in one turn.

I needed something like mobilization centers, but something that can scale with the game's scope, and I happened to see a screenshot of MoO 1 with a stargate on one planet, and realized that there is indeed a solution to this dilemma!

How I envision Stargates working:
You don't have to own planets at a system, just merely have a fleet there, requiring you to actually hold the system. This will allow space-based races to create stargates without planets
Stargates will come in different sizes. The bigger they are, the exponentially more expensive they are to build. However, the upkeep cost will be very low compared to the construction cost, depending on the size, so you don't bankrupt yourself by building a bunch of small stargates.
Different sized ships will require stargates of at least their size to be able to be deployed.
Stargates not only act as a mobilization center, they also perform similar to stargates from MoO 1. There won't be lines connecting different systems because a stargate can connect to any other stargate. The pathfinding code will automatically find the quickest path, with or without stargates.
To travel to another system with a friendly stargate (either yours or an ally's), both stargates must be of the same size or bigger than the biggest ship in your fleet.
To put ships back into reserves, they must be adjacent to a system with a stargate big enough for those ships before you can disband them. This will prevent the "5 turn from anywhere" exploit in MoO 3.
Terraforming and planet building projects can only occur in systems with a stargate. This allows players to build planets in systems with only asteroids or gas giants. It also allows space-based races to terraform planets that they've devoured (replenishing their food source)

This will allow players to build one or two very expensive "Leviathian" sized stargates to be able to mobilize ships of that size, but they can't really travel through stargates due to the cost of the huge stargates. However, a bunch of small ships can more easily travel around. Of course, it's very possible in a huge galaxy to have a lot of Leviathian-sized Stargates due to the number of planets that can support such cost and construction efforts. I think this will do very nicely in balancing reserves/deployment. You can't build a leviathian sized stargate on a system you just conquered in middle of the enemy terrority unless they're stupid enough to leave you alone there for a while. But the smaller ones will be cheaper so it's possible for you to establish a beachhead there.

What I'm unsure about is how Stargates should look in the galaxy map. Should they be a 32x32 icon next to the system similar to fleet icons? This may be confusing because the stargate will be accessible from any position that is adjacent to the system. Also, how to show which size a stargate is? Ideas, suggestions, and feedback are welcome on the whole concept of stargates!