If you lose Wrath V and then get hit by Hoodswing before you regain it.... You lose. :3 Your healer will be OOM very quickly. The presplit Caduceus is only one third of the fight. There's no reason to make your mages heal through higher damage with 2/3rds of the fight still ahead of you. Plus you lose your Crit Buff meaning the fight lasts even longer because it slightly lowers your own hits.

It's just not worth it at that one third of the fight. Grease the incoming heals in the first phase and the fight will be easier and more manageable after the split when the incoming damage is also less.