Can confirm you really have to delete the old block chain and peer data to resynch. No way around this.
Was there ever another way? Lols...
It's unusal that you have to do this when you updated the client before the fork as far as I know. Can't remember that I had to do this for other coins with anounced hardforks. But I might be wrong.
It's just a smart thing to do. Purge it all. Start over. No excuses. Evan had higher expectations than his users could deliver. That's all...