You aim near them the arrow will follow. An arrow shouldn't be able to do damn near 90 degree turns, and I remeber a guided arrow doing that on multiple ocasions.
A decent+ Necro player can put me down after a little time. I also can have problems with Elemental Druids, if they're somewhat smart. I try to 'hit and run' the Druids.
I'd say, ama may hit hard, but a good barb kills anything to my time earned knowledge (since day 1 of diablo), aside 1 thing I can't seem to kill.. a god damn stacking bone or psn necro (necro who has an army of summons and teles which puts them all on top of you because of a bug) thats about all that can kill me barbar