A monetary system that can't be trusted for its primary function (movement of money) is inherently problematic.
The anonymity part for DRK and the trust issue is more like percentages. If you DarkSend the money 5 times, and a bad actor controls like 30% of the network, it's like 0.3 x 0.3 x 0.3 x 0.3 x 0.3 = 0.25% => 99.75% that he'll miss the money flow. You play with probabilities. As you do when you use an IP obfuscation network that might reveal you anyway, whether you use DRK, or MRO.
DRK still doesn't handle change correctly though, which makes it super flawed at the moment (unless I missed the implementation of change denomination pools).
Correct Sir.
RC4 will fix the change issue and be pretty much untracable.