I posted about this same issue: https://forums.elementalgame.com/416432
Looks like I'm not alone in thinking that the way Experience is displayed is too subtle. I think one issue is that the crown used to represent experience isn't given much prominence in other areas. For instance, if a unit gains experience in a quest, does it show that icon?
Also, can anyone confirm if highlighting the crown icon says that it's experience?
Nathan E- you're right the small window that comes up is needlessly small and doesn't have any labels, resulting in the issues we're having!