wglass,
We got your file (thank you) and I Just spent some time testing it and was unable to reproduce any pauses with and without the -vmargs I was using. I did notice that the memory usage jumps about 20mb when opening the file so that might be why no-args was causing the problem since E/ME on start take about 50mb and default heap space from VM is 64.
Let me clarify that optimizations (speed and memory) is a constant and high priority item on our todo list. We spent a lot of time with profilers for the 3.8.2 and future releases to help trim down and tune up the WTP editors that we *digested* into ME. These editors will get better and better over time.