Playing a fiend warlock is polymorphing into a Hezrou an acceptable alternative?

@mikemearls Playing a fiend warlock. IYO is polymorphing into a Hezrou 1/day an acceptable alternative to Sculptor of Flesh?

— Dave Rich (@Hard_Vice) June 23, 2016

In my campaign, I'd allow this if it instead swaped between warlock and a hezrou with distinct personality, goals https://t.co/Cx3eBhBZ4P

— (((Mike Mearls))) (@mikemearls) June 23, 2016