The numbers are as they are, it's a very simple and straightforward list. Perhaps there are too many MiB missions. But looking at North America, which is relatively heavy in these missions: all weights add up to 184, whereas MiB missions take up 43 points, which is less than 25%. So what's your point?
You're not counting hybrid missions. And North America has the highest weight of vanilla missions, other areas are much lower, so that's cherrypicking.
North America - vanilla missions + new alien missions (UFO flyby and Alien Diplomacy) (101/184) 58%, MiB missions (43/184) 23%, Hybrid missions including Hybrib/MIB mission (35/184) 19% - so MIB + Hybrid is 42%
South America, the numbers are 56%, 20%, 24% (44% MiB + hybrid)
Europe - 54%, 24%, 22% (46% combined)
North Africa - 45%, 29%, 26% (55%)
South Africa - 43%, 27%, 30% (57%)
Central Asia, I posted already, but for completeness - 47%, 32%, 21% (53%)
SE Asia - 60%, 26%, 14% (40%)
Does that better illustrate my point?
As I said, now that I know where it's coming from, I can adjust to my heart's content, but I think it should be a little more prominent in the mod's description that about half of the missions will be non-UFO content. I mean, those missions provide little actual progress towards the goal, beyond solder training (and for the hybrid missions, a few more chances to capture a psi-capable alien). I'm most certainly over-simplifying that, and quite likely even missing something there, but that's a quick opinion.
I mean, the other stuff you have put together, the other additions are cool enough without the hybrid/MIB stuff, I'm tempted to do a few play-throughs with them zeroed out completely.
On a side note, I find it odd that the weight of Alien Base missions in Europe is so low. All the playthroughs I've done over the years, I never really noticed how the incidence of base attempts were low there, but I usually have good radar coverage in Europe, so the waves for that mission were always intercepted. I guess it kind of makes sense, larger population density makes it harder to hide a base there.