I think it's pretty clear at this point that Game Freak assigns Pokemon their move pools based on appearance and the inspiration of their design rather than if it's any good. Delphox for example is based on a very specialized type of sorcerer/mage, thus very little variety outside of Fire and some Psychic moves. (luckily it does get the most desired ones)The first batch of baby Pokemon I can understand: they're from the generation that introduced both breeding and happiness evolution, so Gamefreak wanting to
They'd need to rebalance their movepools, too. A lot of more recent Pokemon have much more restricted movepools than the earlier ones, and that could be an issue.
I doubt Game Freak will drastically adjust most pre-gen 5 Pokemon. A good few Pokemon in gen 6 received slight buffs even if a few made little sense, (+10 to Special Attack for Azumarill? Really?) so I get the sense this is the most GF is willing to do in a given generation other than give Mega Evolutions to some. They do seem to recognize that sizable power creep though, as the new Pokemon in this generation were more scattered in their stat spreads. Heck, Goodra, the pseudo-legendary of this generation, has its highest stat in Special Defense rather than in either offense. Even Metagross can't claim to have a defensive stat as its highest stat. (barely. Its Attack just beats its Defense by 5 points)