I can only think of three items right off hand that MPC cheapened from the postwar-era. Putting dummy couplers on both ends of the lower end cars, cheap variations of the General, and the plastic 675. Most of the ultra-cheap stuff was new tooling for the most part.
On the other hand, they seemed to continue adding detail back into the products that Lionel took out in the late 50's and 60's. The geeps and f's come to mind right away. The "collector" line was really pretty good stuff, and in some cases better than the postwar version. I have a 2055 that's pretty loud with very thick paint, and a FARR version of it that's got very nice paint and fairly quiet for an open frame motor.
Some postwar was junk, some MPC was junk, and, honestly, some modern is junk. Some postwar is great, some MPC is great, and some modern is great. Price point determines quality. It did in 1914, and it does in 2014.
