Update (4/21):

We got MUCH better in the last 10 days or so due to practice and Ellay's advice/tips/training video. We gained 80 or so points of rating and finished close to 1600. In our last play stretch, we were winning twice as many as we were losing, so we're excited about playing more this week.

A good rush against us is still problematic, mainly because I can't DPS down folks as fast with 1-2 people CCed or tied up. I think that more +SpellDmg is going to help all around. The team should be getting another piece of vengeful in the next week or two, which will help both resilience/HP pool and spell damage. 2/4 shamans are now 360 Enchanters, so the spell damage looks like 700, 680, 610, 610 for the team. Better, but still a ways to go.

Another common loss mechanism for us is the dreaded "we kill 1-2 and then stall". It's common for us to kill the first guy right away and then have 2 healers keep up with my guys for long enough that we have mana issues or they drop a shammy. This is only happening against teams with two +1800 or more healers. Purging off HoTs and switching targets up does seem to help slightly, but if a team with good gear turtles a bit, it can be tough at times.