I understand where you are coming from. In my opinion the content discovery is more a UI issue, for example on steeve.app both the search and the content ranking is different to what you get on steemit.

The fact is that you are going to use another blockchain and therfore the economics of Dtube will be disconnected from steem. Technically dtube will have the same connection to this blockchain as other video delivery platforms... just another link. Users will need an account on your native blockchain and steem will not even be used for bandwith.