The current release editor doesn't have any hard limits, but it's bound to break on some definition of "Many Discs", as it tries to load the entire release into the session. This should be changed to a more lazy approach where discs are only loaded when needed. This also means the interface needs some way to display data which isn't loaded yet. I am considering an approach where discs can be collapsible on each of the views, where data for that disc will be ajax-ed into the release editor when a disc is opened. On small releases, all discs can be opened by default.