This echoes my thoughts exactly. Right now, we're actually more limited by the JS UI so a couple 100 MBs is the most you can do in a browser otherwise the UI becomes really slow. There's a lot of room for improvement - we're using React and that's causing a bunch of un-needed re-renders right now that we don't need. We probably need to create our own DAG based task management system and use Canvas to render everything - with all that, workflows on much larger files will hopefully become usable.