I hate playing through content and out-leveling the zone I'm in so that everything becomes ridiculously easy. I like my games to have challenge, and while I'm sure I'll want to be a plus subscriber for the included DLC and crowns allotment for silly store purchases, etc, I'll be less thrilled with the XP bonus if I can't turn it off.
I'm probably in the minority, but even if I'm creating a new character and doing content I've done before I'd still like to keep some semblance of challenge. There may be times I'd like to speed a new character up thru the levels and these bonuses will come in handy, but I would really appreciate if any and all could be turned off via settings so that if I want to maintain "traditional" pacing as I level I'll have that option.
If the dev team hasn't considered this I hope they do, as having the option would be helpful for players like me who don't necessary see leveling as a speed race to the highest levels.