There is one thing I am concerned about with the whole Windows 10 thing. All devices are getting Windows 10, but argubbly only WIndows Phone has an ecosystem worth a damn considering it has most of the apps. Are we going to update to W10 Mobile and lose access to all of these apps, or will it support Phone apps.
How I imagine it will work is while there will be one store, previous WP only apps will only appear for phone/ARM tablet users, previous W8 desktop modern apps will only show up in the store for desktop/x86 users, and universal apps will show up in the store for all devices.