Although I am a big proponent of this idea, in the specific case of ETH and Stablecoins I do not think that we should go over 80%. At 85%, if you borrow YFI as much as you can you only need a 18% jump in price to be better off not repaying your loan. A mitigating solution could be to have different collateral rations depending on the asset you borrow. Clearly, If you are providing stablecoins and borrowing stablecoins even a ratio of 95% is not risky.
In general I propose a general rule of thumb of:
-Stablecoins, BTC and ETH 78% (just to beat out the competition)
-Chainlink 65% (same reason)
-Defi blue chips (YFI, SNX) 50%
-Speculative tokens (YFV) 35% provided that they have an incentivized liquidity pool that would make liquidation not too risky
As mentioned on discard having our own flashloan boat in charge of liquidating undercollaterized loans would provide a lot of security to the platform. But even without it , I m sure a lot of devs will set up their own bots.
At the moment I do not see anywhere to access the collateral ratio directly on the platform, It is probably the most important parameter for a loan and should be displayed somewhere. It would be great also to have an accessible ressource which explains clearly liquidations and their parameters.