The ETH language semantics aren't what I'd want for verification proofs, even restricted to a subset. It's possible there are conflicts between the execution model and what would be required for verified, secure contracts.
Similarly, Id want a proof-checked VM for the currency, which ETH is pretty far from supporting.
So verified-ETH would be a larger, more bug-prone project than starting from first principles, developing a language and VM in parallel. (Also, starting a new project gives a chance to change the economics and/or technology used; depending on your views, this might be a benefit.)
Yoichi Hirai has built a formal definition of the EVM in Coq which makes it possible to produce formal proofs of an Ethereum smart contract's correctness:
I either missed it or it didn't exist last time I looked in to ETH. (About a year ago, pre-DAO.)
Either way, this is a major component of what I'd like to see in smart contracts! (The other two major pieces being a verified VM that supports that spec, and a developer library of "standard" contract pieces -- I don't recall being impressed by directly coding for the EVM, and easy-to-use contracts require a library of "standard legalese".)
Most welcome! It was just released so you wouldn't have seen it last year. There was a major push toward more secure smart contacts, in particular using formal verification, after the DAO hack, and the efforts continue to this day.
Similarly, Id want a proof-checked VM for the currency, which ETH is pretty far from supporting.
So verified-ETH would be a larger, more bug-prone project than starting from first principles, developing a language and VM in parallel. (Also, starting a new project gives a chance to change the economics and/or technology used; depending on your views, this might be a benefit.)