In early March we had a couple of deadlocks on the Goerli network. These resulted from clients observing competing out of order blocks and settling on different equally preferred chain head blocks. This EIP proposes a block choice rule that should be deterministic regardless of when the blocks were observed. I have weak opinions as to what the particular rules should be, so if you have better ideas feel free to propose. But I have a strong opinion that first observed should not be one of the rules as that is not deterministic across nodes and is what caused the deadlock.
@karalabe can I get your take?