Adding the ability for developers to reply to reviews is handy, and widely requested by the community at large for years, but there are downsides. There is a high probability that the reviews section in the App Store becomes the de-facto customer support channel because that’s what users will see first. However, this isn’t necessarily a good thing.
Traditional application support software is feature-rich and sophisticated refined over many iterations and versions — standalone companies exist to fulfil this need. Technically, I find it hard to believe that Apple’s infrastructure for composing replies and triaging incoming comments will be up to scratch. iTunes Connect is not known for its ease of use or flexibility. Big companies are not going to like it because it inevitably won’t scale well to managing hundreds of reviews every single day and small indie devs are burdened with another job to do that they might not be able to justify.
I would also guess that the system is going to be pretty limited, like not supporting image attachments (for screenshots) or clickable outbound links. I’m also interested to see whether Apple will allow developers to ask the customer for contact information — like an email address — so they can continue their assistance outside of the iTunes sandbox.
There is also the other can of worms regarding the usual flaws of online communication. The reviews for apps are bad enough as it is and the ability to reply may exacerbate the problem rather than make it better. A badly worded response from a developer can easily incite an angry customer, even if the intention was to be helpful.
Customer support threads could also just clutter up the comments, depending on how they are presented in the interface, which results in a detrimental experience for customers who are simply trying to determine if an app is good or not.
The developer reply feature is not active in the current iOS 10.3 beta so it’s hard to say if this is a legitimate concern. I am secretly hoping Apple takes this opportunity to revamp the design of the reviews section in general.
Whilst Apple should offer the ability for developers to respond to reviews, it shouldn’t become a mandatory thing. I believe Apple should let developers choose whether they want to enable replies for their app; this preference would then be shown to customers when they go to leave a review so they can know whether to expect a reply or not. If developers choose to opt out, the App Store is no worse off than how it has been for the last decade.