Too real. Have you tried Blender's grease pencil?
Also, in case this happens to anyone else: a .fla is secretly a zipped folder! Rename it to a .zip and extract it and you can see all the internals. A corrupt file is usually due to there being invalid XML somewhere in a symbol or the timeline. It takes a lot of effort but you can keep moving frames/library items out of the project folder until Flash thinks it can open the project again to narrow down the offending content, and then put the rest back. I salvaged a lot of work on a NATA entry in 2012 that way.