Wrt transaction times, if I would want to buy DOGE using BTC, and having BLK as collateral, wouldn't the slow BTC confirmations still dictate the swiftness of the trade no matter how fast BLK confirms? i.e. the smart contract would release the collateral only after BTC has gotten its first confirmation (or however many confirms the users have configured)?
In theory DRK isnt trustless because you can still track the blockchain mixer by watching the outputs. I think it would be fairly easy to write a script to reverse it.
If it was that easy, it would've already been done. Believe me, people are trying. It's a whole lot more complicated than a mixer which you can observe, but it's off-topic anyway and too large of a subject to cover here.
Hell, if they really wanted anon, they should try zero knowledge proof. Thats like the holy grail.
It's proven to be hard (impossible?) to set up trustlessly (to prove no more coins can be created out of thin air by those who create the setup parameters) and/or without the proofs getting huge and crippling the performance and scalability.