I have been playing a pretty massive game as well with this mod. Here are my observations so far.
The AI builds less units, but atleast the units it build are useful. I think the AI gave me a harder time before, because he would hit me on so many fronts.
Now the attacks are normally concentrated in a few armies instead of a gazillion militia forces taking provinces left and right with me having to chase them down all over the map, one province behind them the whole time
It may be my imagination, but it seems like my load times have gone way down now that the AI has to use it's forts to produce units. I am at a point in my current game with around 35 nations on a medium sized map where the turn loading would reach a point where I would call it quits. With this mod, the turn processing seems fairly reasonable, and I think it is because the AI does not have to figure out what to do with all those trash units.
I like the mod, I will probably use it for now on in my single player games, or atleast until someone comes up with a more elegant solution to the junk indies and the AIs <3 for them.