I disagree, XBar.
While I've not used EVERY Simmental sire out there, we have used 8 or 10 different ones over the past 10 years, and daughters retained from them - and a previously-used homebred 5/8-3/8 SimAngus bull - have all been significantly smaller-framed than those sired by a half-dozen Shorthorn AI sires and similar number of Angus AI sires(except for a couple of 4.0 frame AN).
That said, we're commercial producers, with no showring aspirations, and truthfully, no idea what 'softening' entails. Breeding for production(primarily high WW), maternal traits, and REA/Mrb/Shr.
Have mostly been stacking influence of Hooks Shear Force 38K, by using several sons/grandsons, but also Dikeman's Sure Bet (54" mature height... that's pretty moderate, I'd say), PRS Blazin' Hot, JF Milestone, and ASR Longevity.