On a battle video in hte 5th gen games I saw a triple battle team include two "Helping Handers" and a Hydreigon in the middle, ready to make use of the boosts with a Normel-Gem Powered Hyper voice. Did CRAZY damage and almost OHKO'd an Umbreon. Imagine a Mega Guardevoir in the middle with that gem equipped; so deadly and so beautiful. Gems, if used correctly were outlets of destruction back in the day.

Actually, Mega Gardevoir can't hold items, but I imagine if it could, that combination would be really deadly. Hydreigon unfortunately probably isn't the most powerful user of the move Hyper Voice, and it can get even worse like you have shown with the Pixilate users. Luckily one can try to stop it with Wide Guard/KOing the spread move user but typically one does not have the luxury of having those options at all times.

I am so not going on triple battles again if they bring back the gems D: Imagine running into a similar one... with two "Helping Handers" and a Kyogre using Water Spout? WITH THE WATER GEM WHEN IT'S RAINING?

Actually Kyogre with Choice Specs would probably be more devastating since they nerfed the gems. Even so, a Kyogre that can use the Gem and at the same time be able to switch its moves according to the situation, can be a deadly threat one doesn't want to deal with.

Anyways, with that said, I believe that the gems are gone for several reasons.

For one, even with the nerf, they are still somewhat overpowered as I believe they give a boost equivalent to the Life Orb without the recoil, and almost no opportunity cost other than the fact that they take up an item slot (which is what all items do, but I suppose one could argue that there may be better items out there like Life Orb), its only a one time use (which still has a problem which I get to later), and the fact that it only affects moves of a certain type (which can be worked around often by letting the wielder use the type of gem of the move they use most). That feels like a relatively low cost for such a powerful item.

Given that most of the official rules use a pick 3/4 out of 6 style, gems could mean everything in the game. I mean, most of the powered up moves can KO the opposition, and one move is all it takes to get the opponent in a bad position. Half the time one only realistically needs to KO one Pokemon to get the upper hand and gems provide such an easy path. This usually means it will turn the competitive game into a simple click the right move and win style matches. I'm not sure this is the best argument around, but I hope you get the idea.

Now I don't believe that they won't release the gems ever in this generation; it's just due to their nature, they probably need to be saved for later. For me, it's always exciting to get new tools to play with in the game even if they are tools we have had before. Let's take move tutors for an example. They usually hide these until the second set of games are released and they always help shake the game up a bit. They breathe some life into previously useless Pokemon by giving them new moves to play with, and perhaps some of these moves are just what they need to get themselves relevant on the competitive scene. This also goes for other items like Soul Dew or the event berries, or perhaps even the blue pentagon legends to some extent. Gems may not do the same thing, but they allow us to play around with the new tools a bit to come up with new strategies, and new ways to play the game. Of course, like the way move tutors are structured, they have to make sure that the gems aren't overpowering the game, but rather balance it. Also, it's a nice way of seeing the game without the items as we can see the differences between a gem-free game and a gem-released game and perhaps find out which one is more preferable.

Due to this, they also give reasons for the player to either pick up the game again or to get the new one where the gems are released. I know Mega Evolutions provide some role in mixing up the game nowadays, but even so, more Mega Evolutions + new items like the gems (or move tutors) give more of an incentive to buy the new games. Sometimes I feel that the game is incomplete or largely irrelevant if it doesn't change the battle structure enough and gems can probably fix that. They could theoretically put the berries on the Global Link or whatever its called, just like they did with the berries but even then, it will be a good reason to pick up the game and play again.

It's really up in the air at this point as to whether or not the gems will be re-released. Are they hidden tools we will get to later, or are they too overpowered to be put back into the game? I guess only time will tell.