Good idea, but a few flaws.
I like the idea of making Katamari into a Flash game. I need to list some flaws, though.
1. Since the game will automatically upgrade to new items as soon as the Katamari is big enough, lots of items appear on-screen at the same time and make the game chug really badly.
2. Once you become big enough, the game just becomes an exercise in rolling a ball around a screen, nothing else. There needs to be a more strategic element, like in the original game.
3. The levels are just squares of terrain with items. Nothing special at all.
If you could fix all this, you'd have a winner Flash game on your hands. For now, though, we'll have to wait for something like that to happen.