I didn't see where anyone else did this, so...
This mod changes the Pioneer cost back to Population, as it was (I'm guessing inadvertently) changed to Guildar in 1.3. Frogboy's video of LH shows the population cost coming back, so I figured there's no point in working on my strategies with the Guildar cost if it's just going to change back to a Population cost, so I just made a mod to fix it. Strategies will still change in LH, but at least it doesn't have to be because of this.
Just drop it into your Mods folder, enable Mods, and it'll replace the Guildar cost for Pioneers with the (intended) Population cost.
http://darkseam.com/fe/PioneerPopCost.xml