It is but I would put it toward the end of your EMH touring. It will eat too much time. Rides like Pooh and Peter Pan will build up long lines by the end of EMH. Seeing Philharmagic early on in your EMH morning will eat up a good 20 precious minutes. Philharmagic holds a lot of people. You'll be able to get into it w/o a long wait even toward the end of the EMHour. If you're really worried about the line getting long, grab a fastpass (the time won't be until after the rest of the park opens) for it and then do the rest of fantasyland (and maybe even Buzz or Haunted Mansion) before you're fastpass time. Then do Philharmagic and maybe a couple other things (Carousel, Carousel of Progress, tea cups) and position yourself at the rope drop for Toontown (an hour after the park opens). Then you'll be in great shape to get on Goofy's Barnstormer (maybe even twice), walk through Mickey/Minnie's house, and grab a few autographs before Toontown gets packed with people.
Just my opinion and maybe others will disagree or have another suggestion for you.
Jess