The mechanical ball-ramp mechanism prevents any true disengagement of the TOD, ever. (This topic has been discussed many times before on this forum.)

The TOD really is beneficial in a great many ways, including aiding braking/decelaration and boosting hard cornering ability, at speed. What you need to remember is that our wise-fathers at ISUZU in Japan thought about all round performance a lot when developing the VX. Therefore, full-time TOD was the way to go to build the best all-round handling SUV ever, at the time. Rock climbing is just one dimension for vehicle pretty much desiged to handle everything, even river fording, and 90 mph interstate traveling. Be happy such a car exists at all, much less modify it for less broad spectrum operation.