I am really excited to read about the plans for payware products to be available via Flightsim.to. It is the absolute perfect match, as you state, a 'one-stop-shop' for all your MSFS add-on needs.
I hope the payware products will be added into your database in such a way that we can be informed of upgrades/new versions; this is a key feature and the reason I currently use Orbx.
I also hope all the developers get on board. I mean it's a no brainer for them, the more places their products are promoted the better. I am for sure going to be a customer if you can build a good product catalogue.
All Flightsim.to needs now is a good news page, the current one is slow, out of date, and almost seems abandon. Get the news page then it is the complete one-stop-shop.
Perhaps you could collaborate with the likes of FSNews (https://fsnews.eu/)
Stay safe everyone