Burn: Your attack is halved, but you can still moves.
Paralysis: Speed is dropped to 25%, but you can still move 75% of the time.
Badly/ Poison: Lose health, but still move
Sleep: Only asleep for 1-3 turns, unless you switch out. Not that bad.
Now, this is why freeze does not have move like Thunder Wave.
Freeze: 20% of thawing out each turn. This DOES NOT add up like:
Turn 1: 20%
Turn 2: 40%
Turn 3: 60%
No, it is only 20% every turn. Say you get frozen Turn 1. You can thaw out next turn, or the 10th, 30th, or 100th. It would be too OP to have a move do that.