Hate me for this but this is where shadowcash steps in...
Hate to be the bearer of bad news, but one of the Monero Devs deanonymized shadowcash already.
https://shnoe.wordpress.com/2016/02/11/de-anonymizing-shadowcash-and-oz-coin/Although, if we are talking just about decentralization, shadowcash is probably more decentralized than dash--it would be hard not to be unless we're comparing it to Ripple.