Maybe this is too easy a target, but I thought that there were a couple of points that would be worthy of the HDTGM treatment:
The destucto-balls that are unleashed on Hawaii,... not only do they avoid children, but they are never acknowledged again after destroying a freeway and a couple of helicopters.
The USS Missouri,... apparently mothballed with full fuel and armament.
Another entry in the "aliens with an incredibly simple weakness" category,... rather than water or microbes, this time they are vulnerable to sunlight. Not unlike the mogwai.
