TVL is not the goal; TVL is a necessary evil. Every dollar locked in a (especially immature) protocol instead of being locked in a simple and secure wallet is to some extent a security risk.

Sometimes we have to take that risk to get valuable benefits, but locking for the sake of locking should be minimized.

TVL is a great starting point but the only way to validate staying power is consistency vs. massive ebbs and flows.
My preference is consistency with revenue and improvement in earnings. 
ENS is a great example.