I don't have firm data to support this, completely anecdotal.
However, pre tower/minion changes, I feel like I would never have a match that would result in less than 100k XP. Now in wins it feels like my matches result in 100-150k XP, and my losses are 50-80k XP.
It may be a byproduct of the matches lasting way shorter amounts of time, however I feel like this winter veil it's just not even worth trying to level heroes for boxes. Then again I don't remember a single game prior to the tower changes that resulted in less than 100k XP.
Once again purely anecdotal. Would love to see data if anyone actually tracks that.
Team Good Guys vs. The Lost Boys
Queens Consorts vs. Ferret's Ferrets
Tespa Collegiate Series
Multiple Smiles vs. Close to Death