To suggest Vaughan has been in good form for the past 5 years is simply untrue.
To suggest that 1.5 years of someone's career is more indicative of a player's ability than the the other 5 is more untrue. Equally the logic behind suggesting that 19 tests is more indicative of a players ability than the other 62 is baffling to say the least. Im sorry, but no can be 'out of form' for 5 years, the idea itself is rather ludicrous to say the very least.
If Vaughan were averaging in the 40s or 50s in Fc cricket and was underperforming by that standard in international cricket, I can somewhat understand your argument. But when someone has been mediocre for 80% of his FC career, it makes little sense to suggest that he should be selected because of what he did for the tiny minority of his career (at the start of this decade).
I do also think that Vaughan's performance in NZ, both during his purple patch as well as most recently provide clear evidence of his weaknesses against the moving ball. Hes always been shockingly poor against it and the majority of his test runs have come on flat batting wickets.
Im very very surprised that anyone can possibly be stunned as to his non-selection for the tour to India (whether it was his own suggestion or otherwise). To expect him to make the tour having barely managed to make double figures since the NZ series would be a joke in itself. If he manages to score a few runs in SA or NZ or whereever he chooses to play, then perhaps his experience might come in handy in India, but otherwise there is little point in selecting a player whose career average and '***y' cover drive flatter his overall playing ability.
As far as the selection for the India tour is concerned, if Swann or worse Bopara, make it ahead of Samit Patel, I will be disgusted to say the least.