Not using the Exp share only means you have to grind more, and grinding is still going to be easy, so really the only difference it makes is the amount of time you spend grinding. I realized this after not using the Exp share in X/Y, that all that accomplished was more time wasting getting my newly caught Pokemon up to par. Your friend was probably overleveled because they grinded too much, which can happen regardless of whether or not you use the experience share. I used the Exp share in Sun/Moon and my Pokemon were at most only a few levels higher than trainer Pokemon... well atleast until I decided to just have Ribombest solo the rest of the game lel.

Not sure we disagree exactly...that ties into my rule about not grinding unless absolutely necessary. My point is that using EXP Share creates experience where there previously was none, meaning that it levels up your overall party faster...which in turn means the overall game will be easier. The other option might be more tedious to you or me...but that's purely subjective. 

Again though...I'm stating ways that make it more fun for me personally. If it's the opposite for someone else...well, fair enough. I beat the Elite 4/Champion with a party 5 levels below any of their Pokemon, and I honestly enjoyed that challenge much more than my X/Y playthrough, in which my team was extremely over-levelled.

S/M were good in terms of difficulty. I'd say theyre the hardest Pokemon games since Red/Blue. But also more fair

S/M fixed X/Y's EXP Share. It's not broken like Gen 6

Well I didn't use X/Y's Exp share so I don't know exactly how OP it was, but I still don't see how you can be overleveled without grinding unless the EXP share also has a Lucky Egg effect. In Sun/Moon it just gives every Pokemon the same amount of experience the lead alone would normally get, so whether you have share on or off, the highest level one of your Pokemon can be at any given point in the game is the same bar grinding.

Hey I have no problem with that, everyone can play the game however! I'm just saying I don't think the Exp share really makes the gameeasier, only take less time. It's just grinding that makes the game even easier in terms of what level your Pokemon are.

up until the near end of the game I was an entire 10 levels above any wild pokemon and at least 5 above any trainer pokemon. but pokemon games were not designed to be overly difficult. if anything, the competitive community has that covered

I think the debate here is that if the game wasn't so easy on the player mechanically, leveling the game faster wouldn't matter. Again, my example is SMT. Pokemon is easy because the player has more freedom and tools than most NPCs. It's why playing against another player is so difficult.

If every NPC could switch to counter your Pokémon, switch when they killed your pokemon knowing what pokemon you were about to send out, had access to every healing item you have and used them as often as you do, built teams better, etc, like you can the game would be much harder regardless of grinding.

Genuinely, try and play an entire Pokemon game on Set without using items during battle and without switching your pokemon during battle. Players have an extremely unfair advantage that has nothing to do with levels

They should do like in BW2 where you could choose the difficulty.

Sun/Moon had a decent difficulty curve, though XY didn't. I feel that so long as challenging post-game content gets in lured, all is well.

I felt Gold and Silver was the last game to have some challenge... and that was mostly due to Whitney and not knowing initially how Strong Red was.