Rate my Summoner Necromancer please.

[Shade]

I have not tried 1.10. Why is blocking now more important than 1.09 (other than I assume the monsters are faster)?

Not only they are faster, but they hit harder, which is usually results in stunlock. Melee monsters aren't a problem, but Bliz boosted archers (e.g. quill rats, returned etc). These guys are real PITA.
So in 1.10 you have to choose - to be stunlocked (and be dead), or to be blocklocked (and have a chance to kill them before they kill you).