>>36585520XY and (especially) ORAS are not at all balanced around Exp share. You MIGHT avoid this in XY if you completely forgo grinding wild Pokemon and trainer rematches, but it is pretty much inevitable in ORAS unless you skip a shitton of trainers.
USUM have the same problems if you're like me and your autism wills you to capture any available Pokemon on route but you can still get cheesed by Totems by some bad luck and poor coverage (ie. Kiawe's trial if you lack rock, ground, or water moves might force you to use X-items and be a sandbag for a turn or three).
