I've had both these lenses and glad that I sold them off before the new ones come out. For the 800mm, Nikon just came out with theirs, so it makes sense for Canon to respond. Especially since most wildlife photographers are trading the 800mm in the the 600mm f/4L IS II ( I did ). They need to redesign the 800mm to make a compelling reason for us to buy it over the less expensive 600mm II. Make it lighter, thinner, give it the mode 3 IS, better weight distribution, etc.
The 200mm could also be refreshed to reduce weight, mode 3 IS, new coatings, more fluorite, etc. Make it start at f/1.8!!!
But looking at this from Canon's perspective, this is economic genius...refresh two already great lenses, give them a new paint job and sell them for double the price!