The price calendar is back on the website... I just tested it by searching Accor properties in WAW and I have the the "See price calendar" link underneath each property.

What's even better is that the rate calendar now pops up as a scrollable list on the right hand side so it's really easy to skim through the dates to see which nights are cheap.

Also, as you scroll down the list of dates, the cheapest night will show a "Best price" box next to it. If you keep scrolling and a lower price appears then the best price will now show against that date instead.