That's a fair assessment; "Oliver" has very little to do with the actual book. The book has far less sympathy for Fagan and Dodger, for instance. The book doesn't try to redeem them, and they're not nearly as much fun as the film interpretations. The musical is very glamorized compared to the...
I'll give you that Goodbye Mr. Chips is a flawed musical. It wouldn't have been had it been a straight remake and they left the songs out--which I believe to be Bricusse's weakest, ever...! Other than that, Peter O'Toole was perfect in that role, although he was a tad young. I have no idea why...