Save ends effects are not pathetic if they take away the next round or two of actions of the BBEG, especially if the PC acquires or crafts magic items (e.g. Illusionist's Gloves, Orb of Ultimate Imposition) that modify the save. Orb of Imposition has been nerfed, but there are still ways to make it difficult to make a save.
How many BBEGs is a PC going to run into in a given day?
It also depends on whether the DM is rolling his dice in front of the players or not.
But, you make a good point. This house rule was implemented pre-WotC nerfing of lockdowns. It's probably not needed anymore. On the other hand, many classes have a way to stun an opponent. When fighting a Named Foe or any solo, a group of well designed PCs could try to tag team stun the foe. I'll probably keep the house rule, but change it for solos only.