Maybe a lot of the pros don't need the torshional stability because they're better at hitting the sweetspot regularly or technology has improved. Berdych uses a ton of lead at 3/9 - maybe it's needed for that particular frame.
I have to put a lot of lead at 3/9 on the YT Prestige MP as it is very harsh without it. I've been playing around with the IG Prestige MP and I don't feel any harshness without the lead at 3/9. Maybe it's better technology or an internal rearrangement of mass but the IG Prestige MP seems to be a better racquet to me. My IGs have a polarized setup while my YTs do not.
4 x IG Prestige MP, 70 cm, 376 grams, 386 SW, ALU Power @54, Prince Syn Gut 16 @58