It's so sad. SCH went from having the most AoE potential with Miasma 2, Bane and Shadowflare to having the fewest with Art of Floor. Personally, I would give SCH back the entire Miasma line (including Miasma 3) as their AoE DoT.

From there, they'd just need to find a way to reincorporate some of SCH's old oGCDs like Bane and Shadowflare and SCH would be fine in regards to its AoE potential.