It depends on the game, honestly. Overall, yes, I have increased in skill. Most of the little games I couldn't play as a 10-year-old, I of course can kick their ass now -- the stupid movie-into-game SNES cartridges, that is. I'm better at adventure games and platformers, but that may or may not be saying much, considering I still think Super Mario Bros. 3 is the hardest thing ever. Chrono Trigger, as good a game as it was, became a cakewalk when I played it on DS, though. I swear that they made it Easy Mode version for the DS, but my friends insist I'm just better at games.
I was saddened to see how formulaic all of the Killer Instinct moves were between characters, though...they all have a projectile with the same button combo, for example. It was sad. So some games got easier, but hard games sometimes just stay hard. (Or get harder, because using an old-school D-pad kicks my ass.)