How could Marvel NOT be paying more than Donmar? Film and theatre generally work on two very different scales.
I find it quite... refreshing how a change of director has drawn such attention. I mean, it's not a 'Rain Man' "someone's sneaking off under the cloak of night and no one will ever know the true reason why..." happenstance, it's much more straight-forward. But to be offered refunds and exchanges because the *director* has changed, when some companies won't even offer refunds or exchanges when the *star* changes? I think that's brilliant!
I know it'd probably be completely different if, say, Michael Grandage couldn't do 'Madame De Sade' so *casts about* Peter Hall took over; there'd be a short news story on here, some "ooh, wonder why that is?" speculation and that'd be it. So while it could be a little disheartening that it's mostly because it's *Kenneth Branagh* backing out, I can't help but find it pleasing that people care who the director is.