Went on a full delta run (eye) earlier, and the Stormbringer has a skillset designed to perfection for performing DD/partial tank with freebie gear.
Only used free morai gear, with some crafted OHT that I've had that is pure phys def adds. Mold for necklace and belt (Sky Demon/Slaughter) with 1,473 unbuffed phys def. Our demon form is on 2 minute cooldown, and would go up in time for the next wave each time.
We can go full out DD, but it isn't recommended at later points unless you have some really good gear. You will steal agro from DB with just the lvl 95 free morai weapon, and the shroud or recast shroud scythe will likely see you able to take agro from pretty much all other classes. Most of the time with DB and some defense aura it won't be a big deal with Demon Form up, and with a good group it should be possible to kill most of them quickly.
Positioning is very helpful in there. Stand right outside the DB of a wizzie, so that mobs travel through and stay inside the DB aura early on. When your form is near ending, use the aoe freeze and then move out to get some distance, and see how many may still be locked on to you. HP and use speed skill to get some distance, or if possible Lunar inside the DB to give damage negation, as well as time for another DD to deal more damage to switch some, or for a tank to fully grab agro before going some more.
We had some DCs during the run, think two people were dual clienting, had BB drop while the boss had phys def debuff on me and mobs still agro locked while running them around to keep alive; didn't have anyone die the entire fight. A well-played SB can even ensure there isn't any unaggro'ed mobs that can get by to drop BB, which seems to happen frequently whenever I cleric in one.
Over-all, with the sheer damage and speed of the AoEs we can get out, and the tank buff we can get during the main part of each wave, we have the potential to be the highest surviving most damage dealing class in there. We can safely keep heal agro from ever happening with ease, and have the ability to cast AoE after AoE non-stop. With end game gear, it should be easily possible to be both DD and tank in there. So if you're looking for relatively easy xp, definitely give Rebirths a go.