The fast versions are nearly impossible to chase down right away. The knockback enemies can hit you once completely negating your progress to engage them and slow you down so you cannot re-engage again. The teleporting ones will not only run away but also teleport away, often in succession. The shielding mobs will prevent you from doing anything to them at all for several seconds, giving them adequate time to flee several times. And the Extra Health ones are just annoying because it takes twice as long to kill them and it can take upwards of 10-15 minutes to chase down an entire pack of these when they split up and head off everywhere.
There are a few other mobs that do this in later Acts, but often the environment aids you in chasing them down or forcing them to double back to you. In the Weeping Hollow area these enemies can traverse the entire game map without any obstruction. As I often use the elites there to build up stacks of NV for Keywarden runs, it has become a glaring problem.
One solution I would suggest is to give them a fixed "Flee Radius" of say 100 yards. Meaning that the enemy will go, at most, 100 yards away from their starting position before being forced to return back toward their starting point. Using their spawn in location as the center make it possible for the mob to flee anywhere within a circle with a radius of 100 yards. How they move and when they move is fine, but if they simply had a limit on how far away they could flee it would solve so many issues and still make them a "challenge".