I appreciate the feedback, you seem to be the first to report back, other than the v1 bug reports.
Here's some feedback.
I love the basic concept of the mod; too many games on the middle difficulties end up with a huge tech gap. On Prince, in most games I'll have a 15-20 tech lead once I'm in the Modern era, with my civ building every wonder before the others even reach those techs. Last night I was gifting Giant Death Robots to city-states at war, and watching them conquer the #2 and #3 civs. (I don't want to bump up to much higher difficulties because of all the OTHER bonuses the AIs get there.)
So yes, returning a Civ4-style Tech Diffusion is a HUGE plus, and I was a bit disturbed to hear that this wasn't in the core game already. I'd personally recommend against stacking in too many features, though; I'd bet a lot of us like the basic concept but don't really want too many hidden factors, especially since human players will be much better at controlling those factors than an AI would. Maybe just make a "Basic" and an "Advanced" version of the mod if you want to continue stacking functionality on. If not, I'll have to integrate the core part of this mod into my own works (with credit attributed, of course) in its most basic form.
That being said, I haven't looked through the code myself, so I have no idea if some of the following are possible, but I'd really like to see several "stubs" added so that users can tweak the tech diffusion through simpler XML changes within their own mods. Changing the starting values is the obvious thing, but I'm talking about integration into other XML files. For instance, I'd like:
1> The ability to only have Tech Diffusion start at a specific tech (for both the person gaining the bonus AND the AIs who are checked)
2> The ability to automatically increase the diffusion rate at certain techs
3> The ability to increase the diffusion rate by building certain buildings/wonders
Let me explain. I'm working on an Alpha Centauri mod, with most of the SMAC tech tree basically stuck onto the end of the modern era. Tech Diffusion would go a long way towards ensuring that the game even makes it to those eras, but I wanted a bit more.
Two of the wonders I was planning had been based on the Civ4 "Internet" wonder (gain a tech if three other civs have it). The Planetary Datalinks was a National wonder that would give you a tech if four others had it, and the endgame Telepathic Matrix world wonder would give you a tech if ANY others had it. But I actually like your diffusion concept better, which means I just need to be able to tweak the values on the fly.
Using your notation, I'd like iTechsBehindReq to start at, say, 8, once you reach Writing. Reaching the Computers technology would change it to 6. Building the Planetary Datalinks would change it to 4. Building the Telepathic Matrix would change it to 1.
So, is this possible?