The onlyOwner role has a single point of failure and onlyOwner can use critical a few functions.
Even if protocol admins/developers are not malicious there is still a chance for Owner keys to be stolen. In such a case, the attacker can cause serious damage to the project due to important functions. In such a case, users who have invested in project will suffer high financial losses.
onlyOwner functions;
This increases the risk of A single point of failure
Add a time lock to  critical functions. Admin-only functions that change critical parameters should emit events and have timelocks. 
Events allow capturing the changed parameters so that off-chain tools/interfaces can register such changes with timelocks that allow users to evaluate them and consider if they would like to engage/exit based on how they perceive the changes as affecting the trustworthiness of the protocol or profitability of the implemented financial services.
Also detail them in documentation and NatSpec comments.
