It would be amazing if there was a way to set up a batch action to do multiple exports. I already use the little lightning bolt profile option to save different sizes/settings I regularly export to, and it would be great to be able to have it do multiples at once. I usually export and then go do something else, because export is pretty slow, and then I forget to come back to do the other one.
Also - speeding up the export would be fabulous. I can export much faster out of lightroom, but use PM to do my captioning so my workflow is
Injest to PM
Sort in PM (much quicker than LR)
Move Selected images to folder -
Import selected folder to LR
Export to Largest size I use
Caption
Export to other sizes for web galleries, etc