Both Zcash and Ethereum are suffering from real world scenarios and self-proved on this. The argument here is strong to protect privacy, however, end users may need a long way to go to adopt a new norm if it’s not usable.
To Ethereum, it’s another issue. It’s getting messy since they’ve put too much efforts onto DAO saving. The code inside Ethereum Core is now like a Gordian Knot, full of hard fork twists.