Don't know, if this is exactly what you are talking about, but I also like some chaining.
E.g. after installation of Photoshop, I want to install a plugin if applicable to this machine/user.
I do not want the user to manually install both applications (where the plugin is not available, because requieremnts (existing photoshop) were not met during last check) or install the plugin, which then pre-install Photoshop.
Users don't want "Plugin", they want "Photoshop" and admins do not want to call the plugin-application Photoshop.
Sync schedule: unfortunately, you are wrong (at least from my experience). I read, that it is synced after every normal update sync. Which is every night for us. But 3rd party was never synced automatically since I've set it up.
But I totally agree with the main request: let us handle 3rd party just the very same way we handle MS updates. Fully sync and let ADR do its job.
Right now, it is more work to publish 3rd party in SCCM than just using SCUP
Works since 1610