Johto is overrated. The only reason it was memorable was because of the fact that it managed to cram in two regions into one game and the fact that it fixed some of Gen 1's balance issues. Fun, but overrated. Not many of the Pokemon were memorable either.
Generation V was the best generation by far (bar the weather wars) thanks to Black 2 and White 2. While Black and White were OK at best, BW2 fixed all of BW's flaws (outside of Team Plasma becoming a generic "Take over the world" organization, though they were still kinda cool). Expanded Pokedex including several old favorites (and finally one without Pikachu), more stuff to do during the postgame, improved soundtrack, expanded region, new forms for Kyurem, the Kami trio, and Keldeo (though the latter is only aesthetic, though it is still pretty cool), shaking grass/dust clouds/rippling water (seriously this should be a thing again, why hasn't it returned)... there's lots to love about these games and I don't see why they get hate.
Morty's Gengar was far worse than Whitney's Miltank.
Stufful and Bewear are far cuter than Eevee or any of its evolutions.
I think Zoroark is cooler than Lucario.
Jirachi is far cuter than Mew.
I prefer Emboar over Infernape and Blaziken.
1) I think this one is more of 50-50 than "unpopular". Johto is kind of divisive nowadays compared to other gens, I believe.
2) BW2 has a lot more attention to minor details than earlier games, too. Seemingly minor things like Roxie's gym having different background musics, as long as you defeat the trainers, or when you have yet to enter, and the such.
3) I defeated it with a Togepi that had just learned Extrasensory in HGSS. Now, if we talk about the originals... at least on par with Miltank. But I guess it does not get as much flak as one would have likely overleveled to get past the third gym.
4) Eevee and the eeveelutions, bar Espeon, Umbreon and shiny Sylveon, are not cute in the first place. Nor Bewear or Stufful (Has the same problem as non-shiny Sylveon - the 'cuteness' seems too forced, but it's otherwise fine), but whatever.
5) and 6) Couldn't care less about any of these four design-wise, so I won't say anything else on the matter.
Now, 7) is a first for me.
And I'll include something here - I really dislike ROM Hacks that change stats, abilities or typing and optionally moveset (Unless it's some sort of setting them to date) with no real reason for that change. Especially if that happens on hard-mode hacks. Which is why I'm glad Drayano included vanilla patches for the ones he did for HGSS and BW2.