My old mod (pre-gold) had many of those kinds of tweaks and choices in there, but they totally screwed up the AI. Given that my group cant often get enough people to play that we can totally dispense with the AIs, the requirement is that they can at least provide interesting opposition in the game.
I'd love to go back and work on a mod that totally cuts the AI lose, but with the number of times I'd actually be able to use it, I just dont think it would be worth all of the time and effort.
I really liked the Devnullmod as it coincided with many of my own mods (in fact, I even got a small mention in the readme.

). Perhaps now that the new Version is out, I'll give it another go, but the quality of the AI is generally not up to the TDM level for singleplayer play. Most of the folks I play with want to learn one mod and stick with it in multi and single player so that is why we had reverted back to the standard tech set.
Another change that I'd like to see again are real trade-offs in ship sizes. Larger ships should get expensive far more quickly. The way it is now, the larger ship classes are marginally more expensive due to all ships having the same general requirements...Bridge, LS, Crew, and ~6 Engines. The 'hull' cost is only equal to its size, and when a ship is totalling at 5700 minerals, the difference between a DS at 300 and a CA at 500 is miniscule. SE3 did a good job of showing the differences because of the Engine requirements on the larger vessels. Also, since they were build by component rather than cost, a larger ship took a LOT more time to build. In SE4 standard, a DS might take 3 turns and CA only 5. Thats just not enough incentive to build DS's once CAs or anything else are available. In my original mod, cost (and therefore build time and upkeep) was a huge factor in the larger hulls, but unfortunately changing a million AI construction files to 'understand' that was too much of a hassle for something I consider a pastime and a hobby.
Anyways, I'll probably get bit by the 'modding bug' again here in the near future. If I make any significant changes, I'll post 'em up here again for folks to see and piddle with.
Thanx,
Talenn