I haven't played Sun/Moon but X/Y had just as many features as Black/White if not more. They streamlined breeding, and EV training. They added in Mega forms to shake up the meta. They stopped adding 150 poorly thought out Poke'mon and instead focused on giving us about 70 well thought out additions. They made the jump from 2D to 3D.

Now, I agree with OP that the main story mode has gotten more linear. And I agree that it is a problem.

They obviously need multiple teams to keep Pokemon as an annualized franchise just like Ubisoft with the AC series and Activision with the COD series but as another pointed out, Giga Wrecker Alt is just a port from PC so I doubt it a whole lot of man power ...

Fixed.

That's not fair. There's nothing wrong with being short-sided. Some people just need glasses. What's wrong with that?

There’s no poorly thought out Pokémon in BW

The problem with Game Freak is that they think the players don't like challenge things like puzzles or non-linear maps. In their minds, if you find yourself in a little more hard situation you will throw your Pokémon cartridge away and gonna do something else. That's why they didn't remade the Battle Frontier em ORAS. They are making the games for two kinds of people: the kids of today that can't stand playing a game for too long, and the people who doesn't care about their in-game experiences and are there just to finish it as fast as possible so they can do what they really want: participate in pokémon battles (official tournment or not). They are also trying to be more cinematc, as they are putting more and more cutscenes in the game. And they are overexaggerating in the lore of the games. At first, the mega-evolution~two kind of universe thing presented in Delta Episode was promising but now they stuffed the games with the idea of warp holes, new universes... every game should now expand that concept making the new games feel more and more chained and enslaved to these ideas

Precious to our world 

Pokémon has never been like AC or COD though. There are a lot of remakes and third versions in the franchise, which I assume take significantly less time to make (especially the 3rd versions). They have only made 7 main games, in 20 years time.

That's always made me curious - I feel like I've seen a lot of debate over whether B2/W2 are their own games, or rather more "ambiguity" than debate. 

What did it add and why does that seem to be not always acknowledged? 

Black 2/White 2 is a direct sequel to BW, so it has a different story, plus it adds a tournament mode. Other than that, it's pretty much the same.