Office 365 store restrictions and SharePoint online add-in permissions for creating sites

[Arik Kalininsky]

Hi,
I submitted an office 365 SharePoint add-in app for certification in the Office Store, and was told that one of the changes required is that I remove the 'Full Control' permission for the app, as it is not supported in the store. My app enables the user to create a new web site based on certain criteria. The add-in works correctly with 'Full Control' permission, but does not work with lower levels such as 'Manage'.
 
If the store does not allow me to use 'Full Control', what permissions or options can I use in order to still be able to create sites on behalf of the user?
Is there a different way to go about having the add-in app create sites in a in an existing site collection? The trigger can be user initiated, or event based.

Sorry for cross-posting, I'm not sure my question should go to the or the Office 365 community. 
I would love to get any ideas or solutions for this - Thanks!

[#2]

Adding @Vesa Juvonen

[#3]

Here's your current options - https://dev.office.com/blogs/combining-store-add-ins-with-high-trust-permissions

Which is not certainly optimal. We are looking for alternative options, but they are not unfortunately ready to be shared.

[#4]

Thanks @Juan Carlos González Martín and @Vesa Juvonen !

Vesa, any ideas whether these alternative options will ever become available? Approximate timeline?

[#5]

Can't unfortunately provide any timeline indications at this point to avoid unexpected delays.