That was hilarious. Thanks. XD
The OP's video pretty much covered my thoughts on /dnc in 99% of in-game activities. But there is one thing it's actually good for.
About the only time you should ever see a DRG/DNC, would be for solo/lowman dynamis currency farming. It's a lot riskier than /mage, but has it's advantages.
/dnc gives you 2 more Ja for procing in dynamis. Between those, jumps, smiting breath, and angon, DRG has quite a lot of JAs to proc with. The faster you get a mob proc'd the faster you can kill it and move one.
You mostly survive off once a min restoring breaths. On DC nightmare mobs, with signet bonus, DRG evasion is actually fairly decent.(But no, don't gear for eva. <,<;;) Waltzes are an emergency measure.
The only reason you'd use reverse flourish, is because you're spamming steps anyway for procs. May as well get some of the TP back. Also makes a good self SC tool in conjunction with jumps. Same thing for haste samba. You use it when you've got excess tp over 100% while waiting to proc something.
Spectral jig certainly is weak. I dunno why they didn't boost it's duration when the did for normal sneak/invis. But the one thing it's really good for, is killing time extensions then hiding before you agro adds. Jump, ws, dead TE, spectral.