Tests seem to indicate that most uses of runLater are no longer necessary. Looks like JS engine developers got their act together! :D
Tweak CanvasService implementation so applySize isn't called when it isn't needed.
Mechanically ensure that one-shot event listeners (like 'load' and 'error') are released after they run since they apparently cause a serious performance penalty in Firefox's cycle collector.
Name some XNA Game functions so they're easier to identify in SPS profiles
Fix time wasted in JSIL.GetNativeSizeOf walking the type graph to compute the size of fields that are reference types.