edit: to add to the discussion on Vanguard, Icefrog wrote a blog a bit before dota 2 came to be about balance of items and heroes. He was of the belief that perfect balance is not when every hero (or item) is viable, but rather when nothing is strong to the point of breaking said balance more than everything else. With that said, Vanguard isn't that great, but it doesn't need to be either. It works in lower tiers of match making (I used to build it all the time, and it was core on most heroes I played pre-nerf in HoN). Something not being used in the professional scene does not neccesarily equate to being up/op or even in need of a change, as the game isn't balanced solely around the professional scene.