It became unlimited in HG/SS, which made it easier, but also more annoying for me when I had Platinum as my hub, because it meant I needed to catch a bunch of junk to trade over to my SS if I grabbed a Pokémon from the GBA games.

Such is life.

Although there are emulators that support loading the GBA games on DS, so if you want that pal park experience you can have it properly even on emulator.