Except it is the other way around, Gen V introduced so many awesome new things and Gen VI threw them all away. Brilliant changing music, an actually appealing plot, a challenging but not brutal post-game facility, loads of ingenious Pokémon designs, etc., while Gen VI added bland characters, terribly unbalanced levels, the new exp. share, Amie in-battle bonuses and O-Powers (quite different from Pass Powers as they don't require online or any effort), among others. Pretty much all the good stuff Gen VI added was mandatory and the least they could have done but for some reason people think it's great, as if they had an option between going 3D or sticking to 2D, having great online connection as of all 3DS games or not improving it. But so much for the Pokémon fandom.
Most of the things that 5th gen added were very minor, and they removed a hell of a lot more than they added. The plot is the only thing that was really a significant improvement, every other aspect was a step backwards for the series. They removed a lot of features and gameplay functions from the game that were pretty standard the last few gens, such as trainer rematches, berry planting, regional gadget apps, Secret Bases, and the Battle Frontier. There were a lot of Pokemon which were technically "new", but quite a few of them were really just replacements for past gen Pokemon, they removed bats and rocks from the cave areas only to replace them with different kinds of bats and rocks, which was pretty redundant, it makes you wonder why they didn't just keep the old ones in the first place. The region design was the worst it's ever been, with no freedom in how you explore the region aside from the option to explore the occasional dungeon off the beaten path and all of the gyms pretty much one short route apart. And the difficulty dropped off sharply in this game, all of the trainers had roster limits and there was plenty of handholding throughout the game. And what did we get in exchange for all of this? Gimmicky new battle styles, a useless communication device, hidden abilities, reusable TMs, and Pokemon Centers fused with Poke Marts. And while these things are neat, they're not exactly groundbreaking things, for the most part they're just minor refinements that don't really have much of an effect on the gameplay. 5th gen brought far too little to the table and removed far too much, and overall it felt like it was trying to reinvent the wheel (which is exactly what the series didn't need, especially in the aspects of the game they changed) to try and convince us that it was new despite the fact that it remained on the DS and was therefore limited in what it could add to the series.
Now 6th gen removed a few things itself, but gameplay wise, it refined what 5th gen had done, brought a few things back, and actually felt like an overall improvement. The regional design was a little better, the region felt a little larger and fuller (although it was lacking in optional areas as a result) than Unova was, so the linearity was slightly more tolerable in this game. There weren't a lot of Pokemon, but the ones they added were fresh and interesting, they felt like worthwhile additions to the game. And because of the transition to the 3DS, there were actual gameplay improvements to the game, such as the 3D graphics, grid-free movement with the Roller Skates, the PSS, Fairy type, and Mega Evolution. You could immediately tell that this was a next gen game and an actual step forward for the series. On top of that, they also brought back a few things that 5th gen removed, such as berry planting. Now it's true that XY did remove a few things that 5th gen did as well, like the plot, Contests (although ORAS is bringing them back), but what they added to XY made up for it, or at least in my opinion. I can see how you might not like 6th gen if you're concerned with the plot, but this basically comes down to different priorities and opinions, most of the people that prefer 6th gen over 5th gen are more concerned with gameplay.
I really wish they'd have just waited until the 3DS for 5th gen, and then combined XY's gameplay with BW's plot. It still would've kind of sucked compared to 4th gen, but the changes to the plot structure in 5th gen and the gameplay improvements of 6th gen would've at least softened the blow of having linear region design, decreased difficulty, and the removal of some gameplay features. But you know, Game Freak doesn't really care about making games that improve on the last.