Designing a service

Hey guys, I've been working for the past three days on Pandora, a service that collects all the shared content from all the slacks channels and emails into one place. For now, we thought we would keep it an OSX app. It is great for user flow, and keeps everything local, BUT it is restrictive to build a service for only users using Mac OS Do you guys think that a product should be made first with an OS in mind, to help with integration, and flow. Or do you think on the contrary that it should be easy and well thought, despite the platforms ? Thank you for your help Cheers, Alex