Ring signature size is still a problem. Yes, it masks the originating address of a transaction. But you know its 1 of N (currently 11 I think?). We know that most people buy coins from exchanges and then send them to their destination. An authority can simply subpoena every top exchange for users for whom any one of the addresses in the ring signature belong to. That's 11 addresses. If we assume the user may have made an intermediate transaction, we can go up two levels. That's 11^2 addresses. Three levels, 11^3. Given normal people's typical usage, monero's anonymity falls to broad subpoena power.