It's a big change, for sure. I'm currently exploring other options for distributing the next version of my ebook software, because there's basically no way to make it sandbox-compliant. Among other things, it needs to call Amazon's Kindlegen tool to convert its "native format" (epub) to Kindle format, and it also allows the users to set their own preferred external HTML editor and image editor. Launching external programs from within the sandbox is disallowed (at least by my interpretation and experiments). You can include multiple binaries in the signed app bundle, but you can't launch third-party tools. Unless things have changed recently, or I overlooked it, there's no entitlement for that.
