Geoff the Medio wrote:
The only motivation for having maintenance I've seen was to slow down players from building too much, but there are plenty of other ways to do this, and it's not necessarily a desirable goal anyway.
Well without maintenance there is no reason you can't have an infinite amount of ships (a hard unit cap is worse) and makeing the dominant strategy to win by outnumbering your opponent. Then again you say there are other ways to deal with it, I'll hold judgement until I hear them but for ships we definitely need something to stop players winning simply through numbers, there's just no fun.
For buildings I wouldn't bother having any maintenance at all, it would be more interesting if each building has its own unique penalty rather than sharing a small drain on your finances, these could also be carefully chosen to increase the strategicness of where to build buildings.
Economic sinkhole: drains nearby planet's economies including your own.
Bioterror labs: If discovered creates lots of unrest, and foreign citizens might pressure their government to pressure you.
Psycorps: A Nazi organisation that trys to overthrow you and create a telepath centric society. Basically they start espionage missions against you.
Geoff the Medio wrote:
A possible alternative way to introduce similar costs is to give some buildings (or ships) abilities that can be manually activated by players which have a cost to use. These could cost any resource deemed appropriate, and would work quite similarly to espoinage or cultural missions, except would presumably have different effects.
I wouldn't make buildings with an on/off switch. It removes the risk from a strategic decision, but a building that has a passive and an active effect could work. Bioterror labs for example may require you to order a tailor made virus before they do anything, but can be discovered even while idle.
I'm not sure what you mean by ships with special abilities, I wouldn't want ordanary ships to have any abilities the player has to activate, its fine in a turn based game, but the battles are real time. Rare flagships that provide something like Age of Mythology god powers would be cool
For colonies themselves, I'm positive towards the idea that in the early days they're a financial drain but unless you've picked an inhospitable environment they become net contributors later, it stops colony spamming from being a good idea. (Some races may even be the exception, if we could balance them out in some other way)