Talenn,
I agree that those kinds of choices would be nice to have, and would add even more flavor to the game. Adding those sounds as if it would be quite a daunting task. I know from experience that what you said about modding is correct. It's hard to do at all, even harder to do right, and then having to tweak things every time a new patch comes out...
In the Devnull mod we did something very similer to engines, making the mid-steps more efficent. My goal as to extend those out even further, for example, Ion-Engines out to level 6 or higher, where each level had increasing levels of efficency, or cheaper cost. Ad then when you switched to a new engine tech you lost all that in favor of more speed, and had to research down that thread. Never got aroud to that, and I was thinking it would have been hell to teach the AI how to use them.
Actually I am thinking about doing a new mod, and just conceding the AI from the start. That was always the limiting factor when working on the Devnull mod. We spent 3 hours in AI tweaking (work) for every one hour of brainstroming and designing new components (fun). In the end some ideas had to be scrapped not because they didn't work, or were unbalancing, but just because we couldn't get the AI to use them correctly. And when it comes to patch updates, that is almost always the majority of the work, making changes because now the AI stopped using something.
But if you think about it, how good is the AI ever? Even the TDM AI can't beat me unless I give them big bonuses or handicap myself in some way. But on the other hand I lose a lot more PBW games than I win. Not to mention I play so many PBW games I don't even have time for solo games, unless I am mod testing AI. So why bother right?
Something I'm going to have to think about some more.
Geoschmo