Johnny Novgorod said:
No, the idea was that you buy a game and catch 'em all, not "choose what content you will lock yourself out of by buying one of the two versions we have for this generation, then buy our latest game because we just shit 100 more Pokemon and not only are we splitting those into the same two games (because lol), we're also not incorporating previous gen Pokemon either, so you gotta keep befriending people or looking for strangers who will have the exact Pokemon you're looking for if you have an internet connection by the way".
http://www.gamefreak.co.jp/blog/dir_english/
Because from what I can tell Junichi is talking about people being together. In other words, interacting with others. In other words, meeting/trading/battling.
They don't offer pokemon from previous generations sometimes because that would nullify the need for previous games to exist in the first place. How on earth will I get a Samurott in my copy of X?! Oh wait, I can easily just:
A. Trade online/In-person (Find a friend who has a spare Oshawott or something)
B. Transfer it from the previous games (Only if I have it)
Do you have a fucking grudge against people or something? The idea is catch 'em all. But honestly it isn't that big a deal to have to trade someone your Haunter to get that Gengar (Usually they'll just give it back if that's the agreement for the trade) If it were as simple as "Walking into this patch of grass until you've caught them all in this area." That'd be boring as shit. (Also REALLY hard to balance considering some pokemon are just OP in single player.