I'd say above average oil consumption is a very well documented problem with the 3.5 in the VX, Trooper, and Axiom (including the direct injection, one-year only version that I own). I've owned a Nissan/Infiniti, Honda, Ford/Mercury, Chrysler/Dodge, Chevy, and even a Jeep and never had oil consumption issues anywhere near as bad as with the Isuzu 3.5 engine. Now those cars all had much worse issues in other areas, but none were at the same level of oil consumption.
True, aggressive oil checking/maintenance can help stave off an engine failure. But just because the engine never fails doesn't mean that it is without design flaws.