Vaughan has actually scored a hell of a lot of runs in English domestic First-Class cricket. Since 2000 IIRR his average for Yorkshire is in the 50s. I too would very much like him to go back, play 4 or 5 games at the start of this current season and score a stack of runs. But sadly, the schedule does not allow for that, and like it or not him not being picked for the First Test against West Indies would be a huge thing, because it would be the man who is designated as England captain not being picked when he's available. And it DOES mean that, say he came back into the Second or Third Test as captain, it would feel very, very strange indeed, to all concerned, not least the man (presumably Strauss) who had captained in his absence.
It's a conondrum to which there is, sadly, no real way to win. There are big problems whatever route you take.