From the announcement it is unclear how the experience points will be received by the hero if i have troops from two villages defending a third village. Let's say, they are even in terms of crop consumption and the hero's home village is village A. If the defense kills off 100 crops worth of attackers, does my hero only get 50 experience points and the rest will go to thin air due to 50% of the defense being from my other village?
experience points will be given for all troops that are in defense. So in your example when only your troops defend from two different villages, hero will get 100 experience points. It is calculated the same way that defense points are calculated.