Saying melees need an anti-zerging monster that they are completely unable to touch sounds a lot more like someone has a ****ed off caster and melee hate than being interested in game balance.
I would love to see every single monster in the game that has any kind of knockdown/trip/overrun/charge ability to HAVE to hit first. Several monsters like wolves and hobgoblins finally lost their 'trip even if they miss' ability, even though bugbears still have it. Minotaurs are somewhat annoying, but only charge once in a while.
But air elementals throw you across the room even when you dont get knocked down, and do it without a hit roll, even if they are paralyzed or dancing - you get close to hit it with a weapon - you get tossed.
If a monster doesnt hit you, it should not be able to apply affects to a player. Period. Or else..give players the ability to stun/trip WITHOUT needing to hit, just trip and its a straight save....which of course would be overpowered.