It's a catch 22 sort of thing.
The problem with animations is that you can't possibly know all you need before you start to set things up, and the system does not work well with constant revisions.
Then the system uses two modes, one for preview, and one for export. Its overly complicated to change things for either side of the argument.
Loadable animations would solve most things, except memory management, which I believe is a canvas issue.