On your first point, again, I'm not talking about the actual speed of the games when I say they feel like a drag. And yes, "from what I hear". What would you like me to say? I haven't played them, but I have heard from many people that Black and White shook up the single player a bit more than they usually do. Is that not true? Is it an issue for me to say that?
Just seems disingenuous when if I said the same thing I'd be gangraped by everyone on this forum faster than you can say "Borderlands 2 sounds like more of the same."
As for BW2, my son has it, and so do a few of my students. My son, who is completely Poketarded and has put more than a hundred hours into BW2 said it's more or less the same thing as BW. For him, that's fine. For you, that's fine. For people who skip Pokemon because it feels like it just spins its wheels from installment to installment, it's not fine.
I'd question what your son finds "more of the same." I mean, yeah, it's the same generation, so there's no new Pokemon and it's the same region. So for someone who only really understands the surface aesthetics of the series, yeah, it's more of the same. But by that definition, every single generation is "OMG totally new!!" and third versions are "WTF this is the same old crap." There's more nuance than that.
As for the Post Game/Battle Frontier stuff, I believe you, but I question the wisdom of hiding the interesting, new, hardcore content behind 25 hours of the same old shit. I realize, again, that's not a problem for you or the fans of Pokemon, but for everyone else, saying "dude, there's great content that may be of interest to you, all you have to do is clear the main game. How's the main game? Oh pretty much the same as it always is, why?" is not going to bring smiles to faces. Can Nintendo just throw a skip button in there or something?
The single player being the same archetype from game to game is only a problem if you want to play every single game. People complaining about Pokemon being the same old, same old, but haven't played it, or haven't played it in a while, is who I don't understand.
And yeah, BW made a concerted effort to change things up a bit. Gold/Silver also changed things up too (in comparison to R/S and D/P) by way of being sequels, among other things. B2W2 being sequels means they can go a bit farther in changing things, too. For Pokemon, the "same old same old" means having a new generation, with a batch of new monsters, and a single new region and villainous team. B2W2 deviate from that, so I question your son's understanding of the series. He probably only meant there aren't new Pokemon, but that isn't the conversation we're having right now.