you can't compare 2 extremely squishy champions to Mordekaiser when talking about the mobility department...that just doesn't work.
There are reasons why bruisers aren't given gap closers or any extremely heavy cc...and that's because with it they'd be broken.
has a short-range pull and some slows
has a speed-up and a silence
...goes where he pleases
Has a delayed slow
The only real exception would maybe be
but his weakness is how long his cc takes to apply and how easy it is to avoid
"But Morde is an AP juggernaut"
yes, you'd be right, but his kit revolves around the same limitations as any other. Heavy damage threat at the cost of not having huge utility or mobility. Giving him a blink would ruin him, because with
(even after a nerf) would provide all the stickiness he needs. A blink lasts enough counterplay to justify it