you should not get hard stuck on values. They require testing to see if they are enough, or to op. Things can be changed for example, you can say “5% reduction in damage from all sources while using a shield”.
Yes it was. there are websites and forums dedicated to this topic, right now that came about AFTER THIS CLASSIC RELEASE.
Your right, “we” do. That is why this suggestion is being made 
So you agree those talents are blah, why are you advocating buffing them will break it then? Shamans dont have defensive abilities like other tanks.