You're right, it wasn't that bad...if you brought counters every single game. It didn't allow for any diversity when teambuilding because it stripped all of the need to be creative with it, since it was so easy to slap chansey into a team and not have to worry about any special threat ever.
I loved using chansey - it was in pretty much 100% of my teams - but I don't want it back. OU is fun now.