Quick answer: GRINDING!
Seriously, this is a problem that has plagued the series since the beginning of time and has lately become a bigger issue. Pokemon Yellow was the first game i ever played and back as a kid i didn't even bother to question the many game mechanics that were sneakily hidden from me. Now it is common knowledge that EV's and IV's exist and so now everybody exploits this knowledge, kinda like i exploit F-ZERO GX by snaking (which i had to do to beat the bloody story mode >.<;).
What it the problem with EV's/IV's you say? well first of all, they are hidden stats, why they are hidden? No one knows. Regardless the main problem with EV's and IV's is the grinding. I like to compare grinding in Pokemon to taking a shot of vodka, it's ok for a while, then you start getting a little drowsy and suddenly your face is attached to your 3ds screen. Considering the fact that the fundamentals of EV's and IV's are that of stat implementation in order to give each Pokemon individual stats, something that games such as Diablo manage to do easily without the need to grind and that game came out around the same time as Pokemon Red/Blue.
So why do we need to grind? Beats me. What do you have to do to grind EV's/IV's? now that is a good question as both EV's and IV's are trained individually so prepare to spend several hours of pain as you prepare your ultimate team because those pokes you trained in the story won't cut it as they have random EV's and IV's. You are simply manipulating a Pokemon's stat values because Game Freak are too stupid to create a good system (seriously, i'd take Final Fantasy X's sphere grid system over this). So what do you actually do? For EV's you have two choices:
Play the worst minigame ever for several minutes
Fight specific Pokemon with the Pokemon you are using over and over again for several minutes
EV training is the least of your problems, though it is rather unnecessary and it's never fun to catch a Pokemon only to put it into super training for several minutes before you can even use it. Before you can even begin EV training though, you have to go through the hell that is IV training. To IV train, you need the patience of an owl, you also need a hell of a lot of luck. Get ready to run around Lumiose city for a few hours. Basicly you need to breed the same pokemon over and over again until it has perfect stats, sounds fun..... well you're wrong, unless you like holding the control stick for long periods of time and running to and from the day care every time you fail, seriously i want to do some battles not go frolicking around the city running around prism tower...
The next thing that is wrong about the metagame is that Pokemon have hidden abilities that are generally more useful than their main abilities. Also, each kind of Pokemon has their own unique traits when it comes to stat growth which leads to and unbalanced roster of Pokemon which is never fun because it means your favorite Pokemon will never stand a chance against other players because they aren't greninja/aegislash etc.
So what do you do? well.... i don't know to be honest, there is no hope either way. My advice is to sell Pokemon X and Y after completing the main game because unlike many of the previous installments, Pokemon X and Y's endgame is exclusively metagaming.
Seriously though, take away the grinding and the metagame will actually be a fun experience. Pokemon Stadium managed it so it's possible for Pokemon X and Y to do the same, just add an egg incubator which lets you get perfect IV's and choose your Pokemon's nature and give Pokemon EV points when they level so that they can put them into whatever stat they want. Simple enough, too bad Game Freak cannot fathom this. Seriously if there's any development team that needs to get with the times it's Game Freak, it's about time they get their heads out of the 90's we're in 2014, just....just look at Path Of Exile would you.... that is character progression right there, you can do exactly the same with Pokemon. I thought that this was a series made for kids, if this is the case then make it accessible Game Freak.
-FLAME SHIELD ON-
Now lets talk about Pokemon Bank, the biggest sack of garbage Nintendo has pooped out since the Wii U. Pokemon Bank has become Nintendo's (and perhaps Game freak's) new way of getting a kid's parent's money by adding a $5.00 yearly fee for a service that was once available to us for free, that is the Poke Transfer service which was once called the Pal Park, Now the Pal Park has been removed in favor of Poke Transfer Which is part of Pokemon Bank. Oh joy! we get to pay yet another $5.00 alongside the $40.00 we pay for the game, this is an absolutely fantastic idea Game Freak, a great idea to degrade your fan base, well it would be if people were actually bothered about this but they aren't really.
It seems most people who play Pokemon wipe their asses with $5.00 at least once a year because they're happy to surrender their hard earned money and possibly more to game freak every year. Oh and people, wake up call, by supporting this, you are also supporting more micro transactions in the future, what's next? Rare/Legendary Pokemon for $10.00? Oh wait, better not give Game Freak/Nintendo any ideas.
People shouldn't have to put up with this... but alas, the gaming community is dense, and the Pokemon community is denser than dense. It doesn't help that many of them are kids but come on, adult players should know better that to support this, especially if they have kids of their own. Pokemon is a series that may go on longer than we think, perhaps into our grandchild's generation.
If you think Pokemon Bank is a good idea, you would be wrong. Cloud services are never a good idea. They're just an excuse to get money because they require server maintenance and honestly, there will be more money coming out of Pokemon Bank than the maintenance guy's payroll. Also let me remind you of what happened to PSN a few years back. Yep, you heard me.
Sometimes when i play Pokemon, i want to punch the screen simply because the game is stupid. I must be either a sucker, a moron or a huge Pokemon fan to persist with the series for so long... when it hasn't changed since 1996.