What split, and why a group cares
Forever renamed Curse of Agony and Curse of Doom to Bane of Agony and Bane of Doom and moved them out of the Curse category. Our Warlock talents guide, drawing on Icy Veins and Mobalytics' copy of the beta tooltips, covers the result: a Warlock can keep a Bane running alongside a Curse such as Curse of the Elements or Curse of Recklessness, which original Classic never allowed.
Blizzard's own race overview treats them as separate categories as well. The Orc racial Shatter Curse grants immunity to Curses and Banes, listed side by side.
For a group, that removes the old conflict. The Warlock assigned a raid curse no longer gives up their damage over time to cover it.

A starting plan for two or more Warlocks
Plan around what is certain. Each utility Curse goes to exactly one Warlock, so nobody overwrites anybody, and Banes are checked on the first pull rather than assumed.
For physical-heavy groups, Curse of Recklessness is the one to watch. A tester on the official forums reported a bigger armour reduction without the old attack power penalty, though Blizzard has not published a final tooltip.
- Assign Curse of the Elements and Curse of Recklessness to one named Warlock each, and agree who covers any other Curse the group needs.
- On the first target, have every Warlock apply Bane of Agony.
- Check the target's debuffs. If both Banes show, they stack per caster; if one replaced the other, agree who keeps the Bane on priority targets.
- Repeat the check after each beta build, since none of these tooltips is final.
In PvP, watch for Orcs
Shatter Curse makes an Orc immune to Curses and Banes and reduces magical damage taken for 8 seconds. While it is up, new Banes and Curses will not land, so hold your reapplication until it ends.
Still to come
Not yet settled by our sources or tested in game:
- Whether two Warlocks' Banes of Agony, or one Warlock's Bane of Agony and another's Bane of Doom, can sit on the same target.
- Whether one Warlock can keep both Banes up at once.
- Whether raids have a debuff limit that could crowd out Banes and Curses.
- Final tooltips for Bane of Agony and the reworked Curse of Recklessness.
Sources
Beta notes are dated because Forever is still changing.
- Wowdee: WoW Forever Warlock Talents, Banes and DemonsOur earlier secondary coverage of the Bane and Curse split, Bane talents and the Curse of Recklessness player report, built on Icy Veins, Mobalytics and official forum threads.
- Blizzard: Create the Hero You Want to Be in World of Warcraft: ForeverOfficial race overview: Shatter Curse grants immunity to Curses and Banes and reduces magical damage taken for 8 seconds.