Glad you pitched in. Not my fave either. Glib and obviously for a star turn.
Which role? Madam Arcati is a small part and Margaret Rutherford was not well-known at all when she was cast. The two wives were the stars of the original stage production. It's only later that it became known as one of the few plays with a showy part for a woman of a certain age who'd already done Lady Bracknell.
But cutting over an hour of running time is excessive. How much would you need to cut before it ceased to be Shakespeare's play at all ?
Your view of what makes a Shakespeare play is different from mine. I don't think you saw any of the Globe to Globe productions. All 2 1/4 hours or less, all in a foreign language and all were perfectly valid productions of Shakespeare's plays. Likewise the Olivier and Branagh films (both 137 minutes apparently) both seemed pretty good to me.