800% also seems excessive, I doubt there will be much demand for a platform that offers such low use of locked funds. But primarily the idea of onboarding synthetic collateral that is backed by cryptocurrencies only to diversify pure cryptocurrency collateral seems circular to me. We could essentially achieve the same thing by just increasing the LR on eth in cdps.
It looks like the synthetix token itself has a decent market cap though. Perhaps this token would make a good proposal for collateral?