Equihash was chosen specifically for its ASIC-resistant properties. The question is whether ASICs are still good or bad for Zcash.
On one side ASICs could lead to centralization of mining. Before we even get there though, I think that pooled-mining is just as much, or even a greater danger than ASICs. Flypool (now Bitfly) has over 51% of hashpower and can do just about whatever they want, including making double-spends and protocol changes if they so choose. Yes, there are incentives for Flypool/Bitfly to not do this, as it would pull the carpet out from under the system, but at this point we’re in a state of blind trust.
Further, miners don’t seem to be interested in taking temporary losses by using a smaller pool in order to balance the system. I mined at a loss for some time to try to balance things, but didn’t see other miners being aware or caring as long as they were making as much profit as possible.
Ignoring the mining pool situation, ASICs have created an arms-race for sha256 where only a few large-players with the ability to research and manufacture chips will have control. @cryptomined has mentioned Bitmain, but the fact is that, love 'em or hate 'em Bitmain is the only legitimate manufacturer actually selling to regular consumers. Bitfury and SBI have both developed chips/boards but don’t sell to the public. Bitmain could have easily mined their own hardware, but instead they have a consumer-sales model which does add more decentralization than Bitfury and SBI. If an ASIC does exist, it might not make sense for that manufacturer to sell to the public. My thought is that a private ASIC would hurt Zcash over the long term.
As to @zooko’s comment that ASICS are more risky, I marginally disagree. Over time coins have tended to fork, giving miners alternatives (Bitcoin Cash as an alternative sha265 algo to Bitcoin). Further, miners focusing on Zcash will generally buy Nvidia cards which are more specifically tailored to Equihash than your AMD card lines. GPU systems are also more involved and require a much greater time investment to setup compared to your buy-a-box ASIC.
I’m really not sure what the answer is. I think someone like @amiller is most suited to fully analyze the risks of changing the POW and if it’s worth it. Further, changing the POW might not be ideal for Nvidia cards, which a lot of Zcash miners use. There are many possible outcomes.
By the way, is anyone looking to purchase a few hundred 1080 tis? 