Hi there, Have been spending time testing out the experience gaining system (OH GOD ITS WEIRD!)
So far I have come forth with some conclusions:
These are all based on combat.
- Also, most of my testing I only noted Base XP gained, a big mistake, will look towards this in the next patch.
Having 2 heroes in a group cuts the base XP in about "half", but not exactly, can be up to 10% off in any direction.
Having non heroes accompany a hero does not lower the Base XP reward from the monsters, not even if a "Sion" is present (An Empire only unit, that works a little like heroes).
Summoning monsters, buffing units or permanent unit enchantments does not effect base xp gained
Some spells lower the XP gained from the encounter, Shrink does NOT, Wither Does. Tested versus a Forest Drake solo, Without spells at all it gave 185 Base XP, Kiting and casting Wither until the drake died (12 withers or so) gave 151 Base XP.
Had to put this somewhere, I might have forgotten something, but I cannot quite figure out what they were thinking 
Edit: Found out how the results screen shows the Base XP gained, so edited all the info to inform this, Am not in the mood to redo wither testing and stack testing before next beta
.
- Also need to see why my units sometimes gets >less< XP than Base XP, Probably a bug.
Sincerely
~ Kongdej