Well, to be fair:
In the Worlds and in LBL he lost to the likes of Bettini, Rebellin and Valverde, who had quite a good finish. It is absolutely no shame to lose a sprint against those, therefore I have a hard time seeing those examples as proof of Fränk having a terrible sprint (keep them coming)
As for the Vuelta I feel like you contradict yourself: first you say Fränk sucks, then you say he should have won the Vuelta. Did you count him as a favourite despite the fact that you knew he sucks? Did you simply assume everyone else in the Vuelta field sucked worse, i.e. Fränk was the least suckiest of 200 suckers?
Personally, I think he has gotten quite impressive results: 5th in the Tour with a f*ed-up knee and 5th in the Vuelta with a metal plate in his shoulder and not having raced for over a month.
For "an ok ardennes specialist who can hold his own in the mountains" two TdF queen stages, two TdS stages and a TdS overall are quite OK I guess.