The opt and opt+shift modifiers are very useful to invoke custom utility functions since apps rarely use them I think the reason for that is because the keys can be used by users for alternate characters such as Ø. And it's perfect! I don't use alternate keys, and I my custom shortcuts don't conflict with third party apps. None of the other modifers can replace opt, since they all are in use by the apps. cmd is virtually used by everyone, ctrl is extensively used by CLI and TUI apps. It's sad to see the possibility to capture opt keys to go away for sandboxed apps. I want to ask to at least keep the possibility for non-sandboxed apps in future macOS versions. Otherwise, it becomes very limiting for advanced users.