I would not even put him in the 10 best players to never win a slam honestly. From his era alone I would put Davydenko and Nalbandian ahead for sure, and possibly Tsonga and/or Ferrer too. In history Miloslav Mecir, Todd Martin, Alex Corretja, Marcelo Rios, and probably Tommy Haas would be higher just off the top of my head.
Eh.
Haas: never made a slam final and never made more than one slam SF in a single year (only made 4 in his whole career).
Davydenko: also never made a slam final, won more titles but never beat any of the big 3 at a slam.
Nalbandian: less titles than Berdych, almost less than HALF the career wins of Berdych too.
Rios: May have gotten to #1 but never made a SF outside of RG. Also almost less than half the career wins of Berdych.
Corretja: also never made a slam SF anywhere but RG (never went past the 2R at Wimbledon and 3R of the AO!!!)
Tsonga and Ferrer are definitely up there and I don't have time to discuss the rest but Berdych is definitely "at least" top 10 best players to never win a slam. His longevity alone is impressive. Slam QF's ranging from 2007-2018. Slam SF's from 2010-2017. First title in 2004, last in 2016.