I think I expected that sooner or latter, after the 100's gonne and receiving more 777's the 200 would go too. Infact this summer when I was on my way to Canada and USA I stopped at Heathrow and I didn't expect to see any 200's but I saw still some of them, not many but a few still. Now regarding the 200's beeing old and dirty, well if you want to know I flew in July from LHR to YYZ in a 747-400 ( G-BNLD ) and I can say that even beeing a 400 series it didn't look too young, I think they will probably install soo the new interior with PTV's but that plane was quite tired ( the interior of course ). Finnally my tribute to the 200 classic, I flew twice:
G-BDXG - 1982 - LHR/JFK - First British Airways clrs
G-BDXF - 1998 - LHR/BOS - 2nd. BA colours clrs
CV990, the Maserati of the skies!