I think building on Contentos after the mainnet is launched would be very interesting. I think the team should also focus on marketing. People need to know what going on in the ecosystem (investors and COS token holders as well). I think thats going to increase COS utility and market value.
One very vital thing you pointed out here Is marketing. COS is not actually new as it appears considering the fact that it's already listed in a top exchange but then alot needs to be done on marketing to create more awareness of about the project. Of course you can't rule out the place of marketing in crypto projects like this. I don't know how active the team is working but then they can really do more