Telephoto Suggestions for Landscapes

I posted a thread a few weeks ago asking your advice on wide angle lenses for landscapes, I decided to go with the TS-E 24mm II (versus the Zeiss 21mm distagon) Now I'd appreciate your input on which lens you'd recommend for distance. I currently own a 70-200mm L F.4 and a 100-400mm L F4.5/5.6. I find the latter is too heavy to lug around all the time so I usually end up leaving it at home. The 70-200mm is okay but I find the sharpness lacking. I'm thinking of getting the 200mm L F/2.8 prime as I've been told it's very sharp. I doubt I'd need a lens with focal length longer than that. If anybody out there owns this lens can you tell me your experiences in using it. Thanks in advance.