buff mord's base ms

what the title says, buff mords base ms, hes so freaking slow and has no cc unless you buy him cc, even with stormraider he still feels slow as hell, all the other high damage high health champions have normal ms, so why is he so freaking slow? i can name at least 10 champions off the back of my head that can outdamage morde and have better health that all have higher ms than him.. even with boots of swiftness all i get is 380 ms.