I find it pretty annoying in gen V when there are so many compartments to keep track of xD In gen I, I usually sorted the items myself in the bag, after what type of items they were and how often I used them. OCD.
But I agree, it became so annoying when the bag was full. Doesn't happen often in newer games, right?
I also hated that you couldn't immediately see the name of a TM move without booting it up in the older generations. Made it a game of chance when you went shopping for one. At least before you realized you could search it up on the internet, derp :]
In other news, Flareon is such an awesome pokémon. Fire type, fluffy, big cute paws... I think it's my new favorite. Couldn't care less about how well/badly it fares in competitive gameplay.