In that case I'll definitely turn off FoW for the AI. Is there any other possible way to stop the AI from sending armies of Pioneers around the map?
Yeah, you need to let them cheat a bit if you want competition... As to the Pioneer Armies, would have to undo LH 1.7:

More seriously, would probably have to reduce the three Expansion AIPriorities (Early/Mid/Late)
<AIPriority InternalName="Expansion">
I increased them a while ago (5, 4, 3 instead of 5, 3, 1), but since LH 1.7 it's been a bit too intense. If you do download XD_AI from the Canon files, try to change it back to 5, 3, and 1 and see how that turns out.
The other way would probably be to increase the Pioneer Wages and see if that reduces the AI urge to build a Pioneer Army.
...I've read some old posts suggesting that when AI Intelligence is set above three, it may give the AI huge research bonuses; making the one set for AIEconomicRatio inaccurate. Has this ever been proven?
Most XtraSavage Difficulties are above Insane. Meaning their AIEconomicRatio is higher than the one set on Insane. Since Insane is set to AIIntelligenceFactor = 10, I can't really set it lower for those XSavage Difficulties. Where I'm getting at is I didn't need to verify the information to create the XSavage Difficulties.
The other thing is once you get to Ridiculous, you will not be competing, at all, with the AI for Research. They will get 2+ Discoveries every time you get one, so it doesn't matter much really. At this point you know you'll be fighting Chain/Plate armor troops with clubs and spears...
_________________________
LH Mods by Primal
XtraDeconstruct
XtraDeconstruct Canons
End of Primal_Savage's quote
Just played my first game with the AI fow cheat and the pioneer spam is much more than I expected. I found it almost impossible to prevent the AI from at least building an outpost in the middle of my territory.
I was wondering: Is it possible to give the AI the ability to scout additional tiles (like the scout ability, but more than just +1 sight) as an alternative to giving the AI the fow cheat? Is this possible to mod in? I believe the scout can see three tiles; maybe let the AI see 4 or 5 tiles?
Thanks in advance.