If you are getting hit by missiles, you are too close. If you have one (or more) active Slow Time bubble(s), you might be able to see them coming. Another good protection is Energy Armor + Force Armor. And, I don't use Teleport.

About your dps, I don't know. I ran some simulations in Character Planner and it showed that a Delsere's template is vastly inferior to a Tal Rasha template (at least in terms of dps).

What I did in my team is sacrifice the dps of one character, so that he can wear 2 pieces of Delsere's, and he can spam Slow Time bubbles with all runes (see template below). The three other characters are basic Tal Rasha dps.

http://eu.battle.net/d3/en/profile/c.../hero/31711726