I like these sorts of endeavours and I really hope you succeed. 4x is my main genre and even thou I've never gotten around to play the old MOO games (scared of because of graphics and UI) I want to take the chance to add a few thoughts that I have gathered concerning this genre. First off a lot of 4x games tend to have limiters to avoid too rapid expansion or more common on the research. The economy usually handles the expansion aspect fairly well. But research tends to be curtailed via planet/colony count. This is something that tends to annoy me a lot. One could fairly easily motivate this by saying that it's because its going to take more resources to spread the development through a large empire but if this is the motivating factor then the game should at least say so. But how to deal with this if you decide to add limiters on research should be given a lot of thought, the easiest and most natural way I feel is to make sure its tied in to the economy and either have some scaling or just make research implementation cost depending on population for example. Next up: more research. Researching is one of the best things with 4x games. I just wanted to add my 2 cents to a research system similar to Space Empires V. Overly complex game which I sadly never really mastered but I could play for hours just handing everything over to the AI and play research director instead.
Civilization 3 flat out capped research speed to 4 turns. No explanation was given. My critique of MoO 2 research implementation would be that mid-game RP cost increase is not steep enough. Early on cost practically doubles (80 -> 150 -> 400 -> 900), making you think twice whicsh field to advance. During the mid-game there are multiple levels between 2000 and 3500 RP price range which you can pass in a few turns and make half a dozen incremental ship design changes before getting them built and deployed. And then there is a big jump at the end (6000 -> 10000) which looks glaringly large in comparison.
Why not base the cost of research to a real life "S" Curve. Where cost of reasearch beginning to End follows a Curve, as there is no reason that Cost should Sky Rocket at the End of a Tech Tree. SEE THIS LINK: The four phases of the technology life-cycle https://en.wikipedia.org/wiki/Technology_life_cycle The TLC may be seen as composed of four phases: The research and development (R&D) phase (sometimes called the "bleeding edge") when incomes from inputs are negative and where the prospects of failure are high The ascent phase when out-of-pocket costs have been recovered and the technology begins to gather strength by going beyond some Point A on the TLC (sometimes called the "leading edge") The maturity phase when gain is high and stable, the region, going into saturation, marked by M, and The decline (or decay phase), after a Point D, of reducing fortunes and utility of the technology. S-curve The shape of the technology lifecycle is often referred to as S-curve.
