The developer of Blocknet actually said i n a video that he has spoken to another dex called DYDX and he would really like to incorporate margin into a DEX. The future should be 100% decentralized open source margin trading.
I actually have some idea of how this could be done. But I encourage you to reach out and advocate to developers to check out projects like DYDX and Blocknet.
Already there are lot of decentralized exchanges are available but people still using centralised exchanges due to the high liquidity of their coin on centralised exchanges,still decentralized exchanges need to evolve more and convince people that it is more secure trade compared to centralised one and till that decentralized will be used by very few people.