I think 10x XP for 3 days is WAY too much. 2x would’ve been enough, maybe even 3x, but 10x?!
One of the reasons people keep playing is to max out all characters and you guys just made it possible to max out most (if not all) characters in a single weekend.
Also lvl 40 characters were often an indicator whether people are experienced with that specific character, now lvl 40 will mean nothing
Same thing about keys really, most people who regularly play this game already have all characters/monsters/perks and are sitting at +100k keys.