I would LOVE for there to be an option to enable Optional Mods to be downloaded when I download or update a modpack. Or at least be able to do so in the Versions menu or Profile Options.
Not only would this be handy, but I think if it was conspicuous enough that most users will notice the option, it would encourage modpack makers to make both a low spec-friendly version and full featured version of their modpacks.
That's a cool idea!
We will review this in our product meetings and log it for future look.
In the meanwhile we are looking at improving the dependency system (improved notification of what is being added or deleted when adding modA that has a dependancy to modB), and this might be an advanced iteration on that.