I think Stern has succeeded in making some of the all time great modern games, there's no way I couldn't give that to them. In my mind they only have one 'failure' that prevents them from being at the same pinnacle as Bally/Williams, and that's that they never did a series of awesome original, unlicensed titles.
Games like Simpsons, Lord of the Rings, Tron, Metallica, looks like Iron Maiden, plenty of great games built on the backs of good licenses that were done well. The recent hand drawn art trend is awesome, to me it's genuine progress over some of the early lackluster packages.
But they don't have an Attack from Mars, or Medieval Madness, or even a Scared Stiff, where they showed they can really create something magical from scratch without riding on the back of existing themes. Maybe the rumored Ritchie title will be a genuine step in that direction?
Until that happens in my mind they can't be completely on top.