Wonder what the longevity is of using a VUE ISS as an anemometer only (in a remote setup) compared to a 6322 anemometer transmitter kit & VP2 anemometer?
No real reason a priori to think that they would be any different. Obviously the Vue has only been around for 18 months or so and so we don't have any hard data on long-term performance in the field. But the few instances I've seen of premature wind speed failure in VP2 vs Vue in the first 18 months of use are pretty much similar in incidence.
To your list of pros and cons I would add:
Pro VP2: The anemometer can be mounted separately/higher than the 6332 so battery change will typically be easier on the VP2 (especially for anyone lucky enough to use a 10m mast in order to measure 'real' wind speeds).
Pro Vue: If the speed (reed) switch does start to go faulty then with the VP2 you typically need a new anemometer whereas with the Vue it's a simple and relatively inexpensive ($60) PCBA board change (that also actually gives you a new T/H sensor, though that won't be relevant in this example).
NB Whether the Hall Effect wind direction sensor in the Vue gives better longevity and better through-life accuracy obviously remains to be seen, but it's a possibility.