Putting a movement speed cap on a particular class or group of classes (You mention Juggernauts, Divers and Skirmishers, as
is a Diver and
is a Skirmisher, and because you don't mention any specific member, I assume you refer to the Juggernaut class as a whole) is a very unfair and one-sided change.
For example, it would make Juggernauts useless, as very few, aside from
,
,
and
have any dashes. The rest either have CC or conditional MS boost in their kits that they have to use to get to, and stay on, a target. Most of them have to use that CC or conditional MS boosts JUST TO GET ON A TARGET in a lot of situations.
Divers, like
and others wouldn't be quite as bad off, as they have their dashes/jumps/blinks or what-have-you to get on targets, but even then, if said target has some form of disengage, and the Diver has to use their engage just to get on them, only to be booted away immediately following, they wouldn't be able to do their job much better than the Juggernauts.
Skirmishers like
would probably fare just as good, if only SLIGHTLY better than the Divers because of their shorter ranged, but also lower Cool-Down dashes/blinks/jumps, as well as their conditional defensive measures (Like
has his Counter Strike E) but, just like the Juggernauts and Divers above, they are just as susceptible to disengage, and can be booted away.
The idea that items like
and others that grant movement speed (Such as
,
and I'm sure there's more I'm forgetting) are intended to be there for those classes to provide ways, through wise use and itemization, to off-set weaknesses in each of these classes, just like the other classes have their own specialized items.
,
and more are for the Assassins, for example. Mages have
, Supports have
or ADC's have
and its upgrade
.
In conclusion, if you were to remove those items, or implement a MS Limit/Max in the game, you would have to apply it to ALL CLASSES. Putting something on one class or a small group of classes or champions is extremely biased and detrimental to the enjoyment of the players of those champions.