I don't know if A.B. Vajpayee deserves "Bharatratna" or not. However, he is far better and cleaner than some others such as M.G.Ramachandran (who didn't look beyond TN), Rajeev Gandhi (who reverted Supreme courts decision on Shaha Bano, responsible for death of 1200 soldiers in Sri Lanka and was also involved in Boforce scam), Morarji Desai (who did no good for the country) etc. who have been honoured with "Bharatratna" in the past.
Vajpeyee is clean and a statesman. He has proved his ability when India conducted nuclear tests in 1998. India did significant progress in financial, road construction and telecom sectors during his tenure.
His performance is far better than some others (mentioned above) who have been honoured with "Bharatratna" in the past.