Having played ballista with some of the greats "back in the day", I can say drk is one of the better jobs in there, even at 75 when gear selection was pretty abysmal. A good drk, good mnk, and good pld were all the most long-standing melee fighters that you had to watch out for.
No consumables is a silly rule, since poison pots are an essential part of ballista to avoid sleep.
I can say from experience it's far more about 'avoiding debuffs' than it is anything else. I recall using tricks like double-resist-stun/bind earrings from cactuar rapido combined with the elementa-resistance ribbon from limbus gave a huge boost to survival. I personally went from fearing some of those melee, to hunting them on BLM. Minus-spell-interuption gear also helps a good deal for casters. At my peak, I had established a gearset that made it nearly impossible to get silenced, since at the time, we had several skilled RDM's had become the biggest pain - constantly silencing people as their first action, which effectively shuts-down any caster (You literally couldn't use echo-drops fast enough, because you'd get re-silenced before the echo-drop action finished)
Back to point, on the DRK, you'd need a resist-stun/bind set, a job that didn't need to cast, and something that could midigate TP gain without the use of utsusemi (poisonga / diaga will eat shadows much faster and easier than you'll be able to keep them up). Assuming he's using Apoc, you'll need to avoid hits in order to stop him from healing himself / gaining haste boons.
This pretty much leaves a very-well geared / skill-capped MNK, and maybe a defensive sam/whm (sam/dnc I think would be harder to manage in a 1v1 melee) are the only things I can think of that would stand a chance. sam/whm can silence with GK fairly easily and self-haste / erase after that, but at the end of the day... without poison pots to avoid sleep and echo drops to remove silence, I imagine it'd be messy as hell.
Edited, Oct 12th 2012 11:05am by FUJILIVES
Posting from just above the generator.