Keeping this off the CoroCoro thread for the sake of coming off as potentially argumentative (just being careful), but in response to your Light-type argument:
I fail to see how 'balancing' has any ties to upgrading to the latest gaming system, it was inevitable that they'd upgrade to the 3DS, that's just progression. Light-types are entirely unnecessary. I know someone whose relatives worked directly for Pokemon Co. and she has confirmed that Light-types would not happen, too, so...
As someone who also played the metagame ages ago I think we can both agree that when a generation is released it doesn't usually feel stale until the new games are released, they keep us busy with sequels/third parts typically introducing move tutors to add a little more to what we have. This keeps the metagame fresh without entirely changing the whole game.
Updating a single move's PP/accuracy is completely different from assessing the entire list of moves to update what would be Light-type or not and how it would react with the Pokemon (who would also need to be revamped for the types).
It's too much to 'spice it up a little'. Spicing things up a little is Hypnosis mistakenly getting an acc boost in Gen IV, a new type is revolutionizing the entire metagame which won't happen, it evolves (horrible pun), it doesn't flip on its back and become something entirely new. Adding Dark-types and Steel-types in Generation II was a cinch because of how few Pokemon there were. As we progress in the generations, I believe we're getting less and less of a chance for types to be added. It's a kind of snowball effect.
Your post did come off as a bit of an attack btw, though I do accept your apology.