While the other Warlocks specs are losing their unique secondary resources (something that saddens me a bit, to be perfectly honest,) Affliction are retaining their Soul Shards, which have been a thing since vanilla and have been a true secondary resource since Cataclysm.
While Warlocks all like a bit of DoTs, Affliction is the Dot-iest Dot spec that ever Dot-ed. The changes coming to the spec are intended primarily to re-focus on that aspect of the class.
As usual, this is based on the Alpha build, so all this is subject to change.
Corruption remains pretty much the same, dealing shadow damage over 14 seconds.
Agony also looks mostly the same, dealing shadow damage over 18 seconds, starting low but getting higher with each tick. However, it also now has a chance on each tick to give you a Soul Shard. It will also maintain its current damage level when refreshed.
I believe the plan is to make Drain Life the main filler spell, dealing damage over six seconds and restoring health to you.
The big change comes with Unstable Affliction, which now costs a Soul Shard and has a 1.5 second cast time. It deals its damage over 8 seconds, but with some overlap protection so that you don't waste Shards if you cast it while it's already up. If the target dies while it's still on it, you'll get the Shard refunded. Also, if it's dispelled, the dispeller takes shadow damage and gets silenced for 4 seconds.
Seed of Corruption has a 2-second cast time, lasting 18 seconds or going off after the target has taken enough damage. It then explodes, dealing Shadow damage and applying Corruption to enemies within 10 yards of the target.
Mastery: Potent Afflictions increases the damage of your Corruption and Agony.
Summon Doomguard and Summon Infernal are now on a 3-minute cooldown (I believe a shared one) and might cost Soul Shards (though it's currently listed as "0 Soul Shards.") These will now function as your major damage cooldowns.
The rotation seems fairly simple before we get into talents and artifact traits:
1. Maintain Agony, being sure to refresh it so that you don't lose its stacks.
2. Maintain Corruption
3. Cast Unstable Affliction, especially if you're close to capping Soul Shards
4. Drain Life (presumably - though WoWHead still has Shadow Bolt listed.)
For AoE situations, Seed of Corruption is your best friend. You'll still want to multi-dot with Agony, but Seed of Corruption will take care of putting Corruption on everything.