I second that except there was no filesize bloat. The plugin itself was quite heavy but the size of a flash site, banner, game and whatnot was based on amount of binary resources inside (images, sounds, videos).
I remember Ad networks limits on flash banner sizes being very strict, less than 15 kBs. This was achievable because of excellent vector graphics capabilities of Flash IDE and plugin.
The problem is that it was hard (read: harder than with regular HTML files) to divide the file into different pages, or to implement progressive downloading, so many sites would download every single asset on the first request.
