Never used Calvin myself in HR but plenty have with great effect. Remember not everyone can either recruit or afford to replace heroes willy nilly and so might have a limited selection. This is the vibe I'm getting from some of the guys who are trying to get the Ironheart Relic. We can advise which ones are worth the limited res these guys have, rather than say 'just use the new heroes'.

Amhose Nekhmet
General Alcibiades
Destroyer Herja

Are usually good bets, you can also try Queen Pen, Mulan and Lancelot. Cianna and Thcy no matter what is said here are difficult to use on pre-LB and aren't likely to give you enough stuns to do the job. So that leaves you with one stunner, Shayd.

The form I used with Veleno, 1 stunner and Herja as a sub to lower the morale after a couple of rounds

Blood Alci Leader
x x Adam
x x Shayd

Anyways something to work with there.