This idea came to me as I was falling asleep, so I suppose it may be kind of ridiculous. For ease of reading, have presented it in #s. Problem: How to make early movement between planets feasible and balanced. 1. Game starts with ACU + ACU planetery transporter. 2. This means ACU can stay on planet, or transport to one other place to start there as well: early on, mid game, or later- but option is there for 1x move. 3. Once ACU has transported away, in order for it to transport back or elsewhere it will have to build an additional ACU planetary transporter. 4. To build another ACU planetary transporter is a tech 2 item. 5. This means that first planet expansion is easy, but second one requires some time 6. other units require a secondary transporter, like a UNIT planetary transporter so they can not use the same device the ACU first used. This idea should help to allow the option of: 1. immediately moving to another planet, but not much beyond that 2. making the ACU planetary transporter unit a valuable target (if the ACU has not transported) as it would prevent the enemy ACU from transporting away before you, giving you time to harvest resources. 3. this should help mitigate the issue of planetary expansion being either too cheap or too expensive as it only allows the ACU to travel, and only 1x until additional transporters build.
You should search for the Rocket Gantry thread, I put forth a good system for working this out already. Mike