Fractional XP
As for new items, I've run several games now with the fractional xp in place without issue, so it so far seems good. It feels to me to fit the future setting to have more precision in this kind of thing too (as opposed to a Fall from Heaven type mod where I think it would feel out of place), but that's just me.
More importantly perhaps, my personal feeling is that the leadership promo is a wee bit overpowered, but using a smaller percentage on it before wasn't wise because you'd get the same issue as with the ginaz promos in an integer based xp system. I'd propose changing it to maybe 75% where it's still powerful but not an automatic gimme gimme for leaders.
Another consideration here is that units will on average gain more xp from combat than before. This is because, to give a hypothetical, a combat situation where victory would give in a fractional system 1.2xp, in an integer system gives 1xp. 1.6xp = 1xp. 2.3xp = 2xp. You get the point, it's almost always rounding down. The only case where this isn't the case is low xp situations (.5xp - .9xp) where it did round up before to the 1xp minimum. I think the amount of extra xp is fine (and balanced by the potentially lower xp in low risk fights) and doesn't cause a problem for normal units (feels very natural as I've played games with it), but it increases the power of a 100% xp boost that much more.
Just as a general note by the way, the new minimum xp from a fight (and xp from retreating) is 0.5.
New Spy Behaivor
I've also made a change to the way espionage units return after a mission or being detected but escaping. Vanilla behavior is to return to the capital, even if the unit was on the other side of the planet, and you have a perfectly good city to retreat to 10 tiles away. In such cases I try to make things act in a way that makes sense -- not a way that's quick and easy to code.
The new behavior picks the three nearest cities(owned by the unit's player obviously), weights them based on the ratio of their distance, and then adds in a slight random element. Without going into the nuts and bolts, the nearer the city, the more likely that's the city it'll return to, though where several cities are relatively similar distances, it won't go to the same one every time (thought still will go to closer cities more often). This is done just to increase immersion and make it less mechanical. Overly mechanical and predictable systems remind you too much you're in a game in my opinion, though the balance between transparency and randomness is always an important balancing act.
I'll definitely use this new system personally, but, as always (given this isn't my mod and all

) feedback is extremely welcome on it's inclusion.
Just one more note on the subject in case it comes up, the major
gameplay impact of this (other than a little less human frustration hopefully) is that given a sufficient supply of espionage points, and a nearby base, a lot more espionage missions can be conducted by a single spy in less time on areas distant from the capital. I personally don't think the primary limit on the frequency of conducting spy missions in such a case should be the travel time there, but rather you're supply of espionage points, and the risk you're willing to take in getting that spy caught (as the more time in enemy territory and the more missions attempted, the more likely he/she will be caught.) So, on those grounds, I personally think it makes for better gameplay.
Chris