One very common scenario is to use a bitcoin address as the identification. This may be used in faucets, mining pool, gambling sites, and maybe future block-chain based exchanges. If address reusing is discouraged, any alternative is suggested? To introduce another identity-> bitcoin address translation layer?
Address-as-identity does not use the blockchain at all.
If people want to hide their trace, they can choose not to reuse addresses. If people don't care, why have to increase the difficulty for them? Why not just let the users to make the decision?
Reusing addresses doesn't merely hurt your own privacy. It hurts
everyone's.
There are also security ramifications. And now adoption issues too.
So you mean BTC is mainly adopted by people wants 100% privacy? On the contrary, it's possible that the majority haven't adopt BTC just because of the anonymity. Most of people heard of BTC but haven't convinced to use them because they think the government will not allow such things to exist. The main objective of BTC foundation is not to increase its anonymity, but to explain to the authority that it's not as anonymous as they think. What you are doing, IMHO, is not helping the BTC but killing it.
For those who wants complete anonymity, they can go for some altcoins supporting it. In my opinion, BTC is supposed to be used by everyone and everywhere as mainstream currency. So please stop doing things like this to push the majority away just for the sake of niche market.