I saw Goodman in the role. He was good. He probably would have gotten even better if he'd been given time to grow into the role. As others have already said, Goodman wasn't going to give anyone a carbon copy of Nathan Lane's performance -- and that is what the production wanted. If Goodman had been a replacement several years into the show, it might not have been a big deal. But the people coming to see THE PRODUCERS wanted a Nathan Lane performance even if it wasn't actually Nathan Lane up on stage.
I never really understood, though, why a British actor with very little name recognition in the States was tapped as a first replacement.
"You travel alone because other people are only there to remind you how much that hook hurts that we all bit down on. Wait for that one day we can bite free and get back out there in space where we belong, sail back over water, over skies, into space, the hook finally out of our mouths and we wander back out there in space spawning to other planets never to return hurrah to earth and we'll look back and can't even see these lives here anymore. Only the taste of blood to remind us we ever existed. The earth is small. We're gone. We're dead. We're safe."
-John Guare, Landscape of the Body