I too have the same feeling while ajmal was surely chucking, you cant be sure in mild cases, or say narine gets reported of a higher angle etc At the same time i feel UWA are just really pissed that icc has moved forward without them and are just playing it out for publicity and bad PR.
We cannot really break it down to mild cases and severe cases. Either someone is chucking or someone is not. Also its possible that UWA, remains confused over where the start point of the trigger should be, but ICC has made up its mind to hold it on the severe side (the one that will have more bowlers called for chucking), and move on with this. So the UWA thing may not be that big a deal.