>and the remaining 5% are also vulnerable to things like warrants at the exchange and timing attacks

I was under the impression that no exchanges handle shielded transactions. What do you mean by timing? I would assume you go t-z-t and leave it quite a while as shielded.

>can't wait for bulletproofs!

Bulletproofs do not help verification time which is why we have low ring size. Going from 5 to 21 ringsize only increases size 8%. 15 is even less, a reasonable compromise on size. There is an unspecified perf target that must be met on verification.