It's quite workable, IMO. The scariest pill manip cards either have SoB (
Piranas) or a round winning bonus (
Shann,
Tremorh, etc.) As these guys would need to pill up a little harder to overcome attack manip clans, that +2 pills bonus wouldn't be nearly as scary as it initially seems. Most attack manip clans already offer a 2-pill benefit against a 7 power with no round-winning bonus.
Moreover, like the
Vortex, they could make up a strong pill-related bonus with shaky base stats.
Vortex abilities help make up for those, but they suffer greatly vs SoA... So you could expect to see something like a 3* with 7/2 +3 Life, and it would compare well to existing cards. They might also have a couple of cards with good all-around stats, but with interesting Backlash abilities. I can imagine a 5* with 8/7 stats but a Backlash of Poison 1 min 1... Comparable to
Selma in many situations, sometimes a bit better, sometimes a bit worse.