good idea, but bitcoin is showing its limits. there is a choice to be made: either you go with centralization through certificates. or you don't. the decision has been made, and so bitcoin will from now on carry on with this very weird identity system we call the internet. address as a proxy is perhaps a viable idea, but as Mike Hearn pointed out, this neglects the fact that in quite a few instances people use proxies, such as coinbase, blockchain.info, etc. so if you weight possible downsides through unexpected attacks against the upside - a somewhat more simple login mechanism - I doubt that there will be much enthusiasm. the consensus of the development crowd is in favor of SSL and CA's, and against web-of-trust. Peter Todd and Gregory Maxwell tend to argue for WoT, but it is not implementable today and making large changes in the protocol is not covered by consensus. perhaps there are some clever hacks to do more interesting things, but it seems unlikely to me. bitcoin will remain a very good store of value, but the window for experimentation is pretty much closed by now.