Ours didn't, purchased June 2010. It's a shame because the raincover used to be standard and is handy.

A bit over 3 kg

It's not really practical to wear onto a plane. The carrier sits onto your hips and reaches all the way to the top of your shoulders, so is a bit longer than normal carry-on luggage.

Even using the straps to hold the carrier in its "flattest" configuation, it is still reasonably bulky and takes about as much space as an umbrella stroller.

We have nested two carriers into each other (imperfectly, they don't fit that well) and put them both in a large soft bag purchased from an outdoor supplier (Anaconda, in Australia), before checking them in with our luggage for domestic and International travel. Our airlines were happy to consider it "equivalent to a stroller" and not include it in our baggage allowance.

They would not have been happy for us to use it up to the boarding gate. Can I suggest that you consider one of the soft slings for that? They are light and fine for short distances.

No extra padding for the knees, but we've never had a problem with that despite owning one for 2 years.

The extendable stand which can be levered out to support the carrier when placed on the ground does not have a scratch guard. We have left the foam wrapping that it shipped with in place, but it is not sturdy and the frame will eventually be scraped.

Note that it would be practical to either use and adhesive rubber strip or to wrap a short length of thermal insulation usually used for hot water pipes around the metal stand.