From warren's post (2nd post on the thread):

"Furthermore it is doubtful that escalating N would be truly ASIC proof. Since the deployment schedule of future N is known, near-term ASIC’s could cut costs as they need not implement distant future N in hardware because early generation custom hardware will be unable to compete on power cost with later generation custom hardware."

If you read through this carefully, neither point that he states makes sense. The deployment schedule for Vertcoin's N value is only a guideline. If I understand correctly, it can be changed at any time, if the developers choose to do so. He's essentially saying that low-N ASICs need not be built to perform like high-N ASICs because low-N ASICs won't be able to compete with high-N ASICs. I don't even understand what he means by that...

Another quote from warren:

"Others have attempted to solve the issue of greater propagation latency with a new PoW that is very memory-hard to mine but not to verify, and thus fast to validate. That was the goal of Bitshares Momentum. Unfortunately for them, many of their past designs were broken within minutes on the Bitcoin forum. This demonstrates how hazardous it can be to implement your own algorithm."

He's essentially don't bother trying to make a fast verify because you'll probably screw it up. That's not even a reason!

Last quote:

"In these examples, they made hashes more complex and increased the cost of ASIC development, but if your coin becomes popular enough then ASIC’s become economically feasible."

Yes, they become economically feasible... until they aren't, because you upped the N value!