I was basing my point on multiple reports/reviews of ultra light wheelsets giving negative performance and resulting in effects as I listed such as poor grip and skipping on rough surfaces.
Very basic physics will also tell you that a rotating part which is 'too light' will also be unable to maintain a rotation for as long under certain operational conditions. Take for example lightweight flywheels in race cars - when fitted to a road car they give negative performance as the RPM drops too low between gear changes as the weight of the part is too low to maintain momentum. It makes sense for this theory to carry over to a wheel. Although obviously this would apply more to the rim/spokes, some effect from the hub would be present.
I also imagine that something again too lightweight could be more susceptible to uneven weightings provided by tubes/tyres/valves.
Who is this ignorant person who knows nothing about racecars? Last I checked they never tried to put the same compression ratio or timing advance into the road car which is would be needed for a accurate comparison. not to mention about a 500 hp difference. Also "certain operational conditions" is no where near specific enough. The lower the MOI the better the performance...PERIOD. better acceleration and deceleration. Trying to achieve some type of flywheel effect on a bicycle is just plain dumb. The amount of increased braking, and watts expended to accelerate said heavier system would just be...unnecessary. Your understanding is flawed, your hypothesis is wrong, and your argument is completely broken. Happy trails