The Rotors are new for this year to fill in a "hole" in the previous lineup. Previously there was no direct match for the Air Jacket. The closest would be the Zip Pants at 159.99 (which are a waterproof overpant), or the Mistral Pants at 239.99, a mesh pant with a wind / waterproof layer.
The Rotor pants are a ventilated mesh pant (no wind or waterproofing) priced at 169.99. The pants have Knox (CE level 1) armor in the knees, the same armor as the Air Jacket does. The hips have EVA padding.
We have some stock photos up at http://www.revzilla.com/product/revit-rotor-pants
We are hoping for them to come in with the rest of the REV'IT line in March.
While I haven't had a chance to try them yet personally my gut on the temperature range they will be will be good for is 65+ which is going to be the same as the Air Jacket. You can extend this temp range by adding some mid layers / thermals.
Other pants new for this year are the Turbine Pants
, the GT2 Leather Pants
, and Aurora Pants
The big differences between the Turbine (first post in the thread at $329.99) and Rotor Pants (169.99) is materials. The Turbines have Superfabric on the impact areas and the better armor - ProLife (CE level 2) . The Turbine pants also include the wind/waterproof layer, and the Rotors do not.