This is an excellent posting, and begs the question -- which of the various plot threads have worn out their welcome (in addition to the stupid "guments").

I asked some of my pals about this. I suggested the restaurant (probably the worst example) and McGarrett's mother. In addition to the "McDanno" baloney you mention above, they mentioned Danny's parents, Tani's brother, anything to do with Gabriel (Chin's villainous brother-in-law), Wo Fat, Kono/Adam soap opera, and oft-missing-in-action Governor of Hawaii.

I told one of these people "be careful, you are moving in the direction of 'every thread on the show has worn out its welcome'!!"