Krajicek and Ivanisevic are far more talented player than Ferrer. Their serves alone are worth more than Ferrer's entire 'game'. They won Slams because they had the weapons to beat the best players of their era in the super fast grass of Wimbledon, it's far from an atrocity.
You are allowing your bias get better of you, as usual. By no means does a serve bot deserve a slam. I have watched plenty of Ivanisievic matches. His ground game made my eyes bleed, he was basically a worse version of Isner of that era. Serving on a fast surface and doing not much else and capturing the biggest title in the sport is somehow fine. While a guy who worked hard all his life, has solid consistency, decent ground game - but never made a slam final or won masters because he admittedly lacks weapons is now an atrocity?
Just because you can serve players off court does not make you good, skilled or deserving. Players like Goran and Krajicek would never approach a title beyond 250 today.