Of course there are other ways to do it, but that doesn't make this a bad idea. As the OP said, the current method is clunky, particularly the distinction between PC/Monster (not to mention that token sizes based on sheet data would be so much better than remembering how many squares/hexes this particular size of monster occupies). Dropping a png graphic on the sheet to create the token would also let players customize their token, the way they can their portrait, rather than having to mail a png to the DM and asking "can you please re-do all your work for this new one I found?". The DM needs to be able to modify the token once it's dropped on the map (I frequently adjust auras on my players' tokens, for example, and I play a Rune Knight in 5E and my DM has to adjust the token's size every time I invoke Giant's Might). But setting up the defaults automatically? Very nice to have. +1