I think the DS Era of games are the new Gen 1 in the sense that people are seeing it as the peak of the franchise and everything that came after as worse in comparison.
If you mean that their high status in online discussion now is driven by nostalgia, then I think you're partially correct. I think we're starting to see the 3DS games get the same treatment as the kids who were raised on those get on the Internet and start making posts/videos. That said, everyone thinks the main series games peaked
somewhere, and I think the DS games are a good pick. They get off to a pretty brutal start with D/P, but by the end of the system's lifespan, it feels to me like they really master the hardware and use it to create some pretty great games. B2/W2 in particular benefited from them not having to make every fucking asset from scratch and being able to focus more on extra content, something more of these games should really take advantage of!
DPPt's Routes lacked variety. Like almost every Route had a Bidoof, Geodude, or Zubat (or their evos) in them, which got really annoying after a while.
This stuck out to me playing the remakes, yeah. Even ignoring the encounters for a second, it's all bland grass and caves for the most part, and it just gets to be aesthetically dull, especially in the middle portion of the game. On the whole, I feel like Sinnoh as a landscape is carried by Mt. Coronet.
On a related note: Did every fucking Galactic grunt in this game
really need a Wurmple (or member of its line)? I swear, I thought that evolutionary line was native to Sinnoh for a while.
HGSS still has GSC's wonky level curve, in addition to some final evos being accessable IN THE POSTGAME.
Honestly, the inaccessibility of some of the new evolutions never bothered me that much. They've always felt like fun post-game rewards to me (sort of like the Pupitar line in Mt. Silver), but I can understand why people feel differently with the Johto Dex being as thin as it is.
The level curve is inexcusable, though. I cannot fathom why this wasn't tweaked so it would suck less to actually use a full team, but at least you get a level 50 legendary and can spam healing items through the worst parts of it.
BW doesn't have much postgame content (which is ironically the same criticism I see for the modern games).
I object less to the quantity of post-game content (getting to explore three new cities and see a bunch of landmarks is cool; I enjoy the story-related events like hunting down the Sages and getting a proper fight with Alder; and there's always the Battle Subway if you want a hardcore battling experience to throw yourself at forever) and more to the absurd level spike that all the post-game areas have. I feel like I have to grind ten levels before I do any of the new stuff, or I'll be fighting for my life the entire time. It sucks.
B2W2 fixes that, but I have a hard time following the story.
I don't really understand this, though. It's a pretty simple story; without N, Team Plasma have dropped the act and are just generically evil bad guys who want to conquer the world. Their plan isn't that complicated, either: They're just trying to get a big legendary to impose their will on the region with. All the supporting characters have pretty simple motivations for the most part, and the closest thing to a "twist" is N coming back to help you stop Ghetsis.
If anything i'd take this even further. I think the DS era is the worst era of Pokemon. DP has a laughable story, bad characters, terrible gamespeed, and a surprisingly unimpressive set of new mons - an annoying number of them being postgame only iirc. Platinum fixes some of this but not all of it. HGSS preserved all the flaws of GSC while replacing its distinctive spritework and music with generic equivalents. BW has an inch-deep plot and a dex full of filler, which retreads the basic-ness of earlier gens with less charm and creativity. A lot of the postgame content of all these games is not what it's cracked up to be, featuring dismal rewards, unimpressive luck bs, and lots of sitting around for loading and waiting. Their lore is often childish too.
These games bring some good stuff to the table - i don't despise them or anything, i think they're fine - but i think the fanbase's glazing for them is another Gen1 wave like you say.
This one, I just can't get behind. They have flaws, sure, and I only object to a few of these criticisms (I like the aesthetic of HG/SS a lot, and B/W's Dex is deeper than you give it credit for) but
the worst era of the franchise? There's no universe where that isn't gen 1. That said, with the exception of B2/W2, I do agree that the DS-era post-games aren't all they're cracked up to be (unless you really like the Battle Frontier in gen 4, which means putting up with a lot of tedious bullshit in games that already run too slow — I don't know why they were so scared to push the hardware at first; it's not like these are super fast games where you need quick reflexes and precise execution, and any amount of slowdown can fuck your shit up).
I do have to wonder, though, if the glazing of the 3DS games that will surely be upon us soon will really match the glazing of the DS games. I know people who got into these games as adults, and they pretty much share the current consensus that gens 3-5 are the best, so I wonder how much the incoming nostalgia from gen 6/7 kids will be able to counteract that.