Looking on Gatherer there are actually a very awkward number of white and green minotaurs that can't be in a Naheb deck. Like, you can't put Boros Reckoner in such a deck at all.
Mana Leak can be a miserable card, so I can see why they avoid printing it.
Mana Leak can be miserable, but I'd easily have every card I ever cast be countered by a Blue Mage then have my Opponent get to bash me with Gideon/Kiran for 9 on turn 5
But it did cause issues last time. Delver was a super hated deck and that plus Snapcaster was probably a bit too good.
Delver/Snapcaster/Geist were the issues there though, not Mana Leak. Delver is a card that has created entire Legacy Strategies, there's no reason to look at that format and go "It's the card that's been fine in Standard before that's to blame" when Delver was running around.
I think the biggest problem Development has here is that they probably really do have the sword of Damocles over their heads, and they have no choice but to bet it all that Amonkhet will somehow fix it. Given what we know about the dev cycle for the set, this doesn't bode well.
Is there a version of the Whiteboard Meme for Standard right now? Like,
"This will Save Standard!"
Collected Company Rotating?
More Inventions?
Kaladesh releasing?
Standard Showdown?
Emergency Bannings of 3 Cards you can get in Standard Showdown packs?
Aether Revolt Releasing?
Pushing Temur Tower as a third deck in a two deck meta?
Emergency Bannings of 3 more cards?
Amonkhet Releasing?
I mean, it's kind of getting absurd right now.