Vettori should be on par with Flintoff, solely for the fact that, for so much of his Test career, he was it. Needed runs because the batsmen sucked? Vettori. Needed overs because the bowlers sucked? Vettori. Needed a captain because nobody else had a clue? Vettori. Selection dilemma to be solved? Another job for DV.
In 2008 I'm pretty sure NZC would have got him to drive the team bus if the regular called in sick. He was that versatile and that used to wearing a stack of different hats.
And he'd always find a way to contribute to the team, no matter what role he was playing. For a bloke with his technique to average 30 overall, 39 under his own leadership (the 'Vettori is it' period) and 40 from #8, is pretty bloody remarkable. As is taking 360 Test poles without a functioning back, at a pretty decent career average considering the workload he carried and that he was bowling finger spin in NZ. And even when he wasn't taking wickets, he was containing -- remove the single game in Pakistan in 2002, and there isn't a single country in which he went for >3rpo (Aus the highest at 2.87, where his 37 @ 40 puts him pretty close to elite company in terms of visiting spinners).
He's a significantly better Test cricketer than Shane bloody Watson, that's for damn sure.