My last job, I had a Thinkpad T520, which was just as thick but a bit lighter and smaller footprint. At home I have a T420, again same thickness but slightly smaller footprint yet. I'm no stranger to Thinkpads. I hope I don't ever have to use another.
Even IBM is disillusioned by the Thinkpads. They created the damn thing and they're abandoning it for Macbooks: http://www.theverge.com/2015/8/5/9099451/ibm-apple-enterpris...
I only continued to buy Thinkpads because I knew how to remove all of the Lenovo crapware the moment I got the computer. Especially with the latest privacy issues, Thinkpads are no longer the computers you buy when you just want a solid computer without frills.
The W series and the T520's though... they were always too big to be real laptops and too wimpy to match desktops. It's an awkward place to be.
I travel a lot, sometimes for work, sometimes for leisure, so when I chose my personal computer I went with a Thinkpad X230. Fast enough to compile C++ code for my game programming hobby, fast enough to do my excel stuff for work, and the integrated graphics card can drive two external 1920x1200 screens comfortably. Just don't expect to play any graphically intensive games. With the help of a spare battery I kept around I could get 12-14 hours out of it if, for example, I were flying to Asia.
My point being, perhaps your experience had more to do with being given a computer that definitely did not fit your work/life style? Though I'd agree with you that the W520 was not well designed.