It’s horses for courses at the end of the day.
I think the E-class estate is a great family car if you only need five seats. If you need six or more it has to be something else - for me I moved onto the GL-class four or so years back.
I don’t think I’d go back. Sure the E-class drives better as you’d expect but the space and practicality of the GL is immense.
If you’re not in the market for something like an SUV then you’d probably not get the appeal. Same as someone with a family or a dog or whatever wouldn’t want an SLK or SL etc. Second guessing someone’s reasoning for their choice of car is a bit silly really unless you know them well!
Manufacturers clearly know their market and wouldn’t make changes to their offerings if it wasn’t in their best interests. They don’t usually get this sort of stuff wrong