And the award for worst gen in the entire series goes too...
Gen 5. Easily.

>Ugly abomination tier Pokemon designs made by literal who's and an American who thinks juvenile looking sentient Ice Cream is even remotely good
>Pigeonholed into using these ugly as fuck mons throughout your playthrough, what the fuck who wants to go an an adventure with any of these things lmao
>Absolute worst starters in the series consisting of ALL 3 OF THEM being absolutely hideous
>Worst ratio of good to bad Pokemon we've ever had (literally 90% of the dex is straight up awful looking uninspired tripe)
>Blandest and most linear region to date, having no noteworthy and memorable landmarks.
>Cringe worthy story
>Ugly robotic looking moving sprites that are overly saturated
>One dimensional and completely forgettable characters
>The worst and most disappointing selection of gym leaders, elite 4 and champion we've ever had
>Started the trend of gym leaders and elite 4 having less Pokemon
>Piss easy difficulty, they had to put challenge mode (which literally is only there to 'normalize' the difficulty to what every other Pokemon game is usually at due to gen 5 being innately more casual than every other game in its base difficulty) into the game to compensate for that fact

There's a reason why gen 5 is universally hated outside of /vp/, and these are a combination of all of those reasons.
You go to any other big named Pokemon website and check the polls, gen 5 always comes last.
>B-b-but sun and moon
Yes, even Sun and Moon rate higher. Pic related is just 1 (ONE) example of that.

The only people who like gen 5 are mentally stunted manchildren or people who grew up with it as their first game who are now seething that they missed Pokemon's golden age.
Gamefreak is ACTIVELY trying to distance themselves from the mistake that is gen 5, they knew they fucked up. The piss poor sales and reviews gen 5 garnered shows that off all too clearly.
Gen6/7 have tried to fix the damage gen5 inflicted