Recently the EOS Amsterdam team published an in-depth explanation on Dan's Staking Pool, which he introduced at his latest Governance Proposal.
The explanation focuses on the operation of staking pools, their strengths and weaknesses. In fact it could be possible to overcome the tokens lock by tokenizing the staked EOS and making them liquid, but at the same time we will be able to increase the engagement for voters and it will be no longer feasible for the exchanges to vote.
"Exchanges need to remain fairly liquid. They therefore cannot stake the EOS they hold for their clients for a long term. They also cannot work with “secondary” tokens to make “their” EOS liquid: if their clients want their EOS to be sold, they just cannot offer to instead sell the “secondary” token."