Please please please listen. Make the fields editable.
I so rarely use just a plain zombie, wolf, derro, etc. instead I, the AP or module adds to the creature in some way (Advanced, elite, large, small, disease, young, old, class levels, etc and etc). If I could edit your creature cards I could save myself so much time and these would be must have items.
Let's says I want to add a sorcerer levels to a derro. Currently I have to recreate that from scratch with your 3.5 or Pathfinder free initiative cards. However, if I could edit your derro card I could do it in 1/2 or 1/3 the time.
Even if I'm just adding treasure like a stat boost item that I want to remember and track on the monster having the fields editable would be a huge time saver.
Again the way they are is good, for when I want an out of the book creature... But if you read your mods and AP these guys like to add character to their monsters.
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If you worry about people stepping on the original you don't need to as they can always re-download the original.