I suppose with tokenized assets, there's always trust involved. Even if you could use a DEX to trade tokens that are built on decentralized platforms, you still have to trust that the issuer will redeem them for real assets.
We're seeing this situation with new stablecoins like PAX.
Paxos is analyzing the blockchain and freezing funds when customers attempt to deposit and redeem for real dollars. This will unfortunately become commonplace in the future. The idea of tokenized assets seems great if it means you can avoid KYC by trading on P2P or DEX markets. Unfortunately, the centralized issuer model can throw a wrench into such plans.
And this is why I'm so skeptical about many blockchain projects, they so often end up having some centralized body in its core that connects their blockchain with real world, thus defeating the whole purpose of the blockchain. After that the only good thing left is publicity and immutability, but those things are not always great - publicity means no privacy, which is bad in many cases, and immutability means that errors are permanent. This again means that blockchain has many limits and can't be slapped onto everything in this world.