The only thing I listed that is even remotely a social interaction is the Trade Board.
Look at it from my point of view. For a long time I did not have access to the GTS or the Trade Board. No one I knew had a DS let alone a Pokemon game. I had only one DS so I couldn't trade between my self. My only option for older Pokemon was Pal Park.
I'm just saying, we shouldn't have to do all these things just to get some older Pokemon. Not everyone has access to high speed internet or have friends that also have the game. I didn't for a while.
Basically gamefreak just assumes you have more than one ds (sibce there have been so many versions) and multiple games. If not they expect you to go buy the old games or trade for the pokes. Perfectly reasonable way to make money. Never sold any of my pokemon games or ds so it never bothered me.
They also assume that we all live close to a GameStop or TRU that participate in the events. I doubt there is a TRU in my entire state and I wouldn't be surprised if my GameStop doesn't do the events. One more event I will miss.
You can always ask for a trade on the boards. I tend to miss the events too. More out of lazyness than anything. Don't feel the need to travel to stores just to get pokemon. (Though the last event I remember.....think it was for genosect I just forgot in general)
Going by what is on the list and what I have found in-game so far it seems that most of what they left out were the more mediocre Pokemon. With some exceptions of course (like Scyther's line and Gastly's line).