In the beginning of the anime, Hisoka point blank tells Netero he wants to fight him, but Netero ignores him. This is significant because as stated during the fight with Meruem, Netero has been bored for a long time and is grateful to have a chance to fight someone that could kill him. Again, he ignored Hisoka, not because Hisoka was hiding his bloodlust or aura (the examiners felt it and so did the other applicants; also, he almost killed an examiner the last time he took the test, so it would be odd if Netero wasn't aware of him.)
Yet, did Netero fight him? Nope. He just ignored him. So Netero clearly doesn't find Hisoka to be worth fighting. And why should he? We have seen Hisoka go all out already in his fight with Chrollo and he showed no other ability than his gum... and while a flexible use of nen, it provides him with no way of hurting someone like Netero. Netero's fight with the King dealt thousands of punches in the blink of an eye. Hisoka has shown no such speed or endurance to tank attacks of that caliber. Sun and Moon, the attack Chrollo uses to kill Hisoka, explodes Heaven Arena, sure, but Netero's Zero Hand melted stone! There would be nothing left from Hisoka. And yet, Meruem tanked all those attacks from Netero.
So yes, I would put him way above Hisoka. What can Hisoka do? Throw a card? Won't damage the King's skin. Hold him down with gum? Hisoka couldn't move Razor's puppet and had to release the nen gum. I seriously doubt he could stop Meruem from moving. One slap from the King's tail and Hisoka is dead. Hisoka is not fast enough to dodge an attack from the Ant King.
Now Hisoka wanting to fight Ging... his bloodlust clouds his vision. He wanted to fight Netero, and he could never win that fight. He wanted to fight Chrollo and Chrollo killed him. I would also like to point out Killua thought he could kill Netero during the exam... so clearly rankings by Killua or Hisoka are not to be relied on.