The second-system effect (also known as second-system syndrome) is the tendency of small, elegant, and successful systems to be plagued with feature creep due to inflated expectations.
The phrase was first used by Fred Brooks in his book The Mythical Man-Month. It described the jump from a set of simple operating systems on the IBM 700/7000 series to OS/360 on the 360 series.
References
Second-system effect Wikipedia(Text) CC BY-SA