Mark:
There are many arguments pro and con about Seminole -- how much Dick Wilson changed it, whether that was an overall improvement (most agree the 18th hole is better), and whether Brian Silva's semi-restoration was an improvement or not.
Most people agree that Trent Jones' work at Oakland Hills (South) was an improvement, even if few really know what the Ross course was like. Likewise, the addition to the far end of Royal Dornoch must be considered a success.
Courses that were redesigned and NOT made better -- Inverness, Oak Hill (East), Scioto, Commonwealth.
I'd like to think that our work at Atlantic City CC consitutes an improvement, but if so, it's partly because the course had already drifted well away from the original design due to tinkering and to housing developed on the perimeter.