Please don't abuse the word micro-intensive if u do not know how to use it in the right places =.="

4 heroes???
Oh my god... you don't even know what's the different between a hero and a creep.
Most of the creep (in DOTA) have only 1 skill. How to compare with heroes which has 4 skills.
There is only one neutral creep that has 2 skills.

As for melee game, most of the time you will get 2 heroes, which means you have to KNOW WHEN TO CAST WHAT FOR 2 HEROES (as compared to DOTA 1 HERO).

As for spell casting units , you will need to know when to cast what spell (from heal, inner fire, blood lust, cripple, unholy frenzy... too many spell to list down).
To make it simple, each of sorceress, witch doctor, necromancer, druid of wind ... etc.. has 3 skills to use.
As for other units, some of them also have skills, like dragon hawk rider, footman etc...
And you get to control like 10 to 20 of them during a battle...

Melee game pro players are able to control each and every unit separately to get maximum efficiency.

In term of micromanagement, for pro melee game player can control a hell lot better than DOTA.
BTW, whatever you reply on this, I won't bother to answer anymore.