Concur.  Bitmain suggests creating a wifi bridge using a second wifi router as a client for your main router. I can't figure out how to do this and maintain an acceptable level of security for other devices on my network, so I fell back to hardwire.  I imagine it is possible to create such a bridge, I just don't know enough about networking to do so comfortably. 

I really don't know why BitMain moved away from the the controller board they used in the S1 and S3 (well I guess I do...the answer is cost).  This is unfortunate; wifi is/was a great option for me.  I never had an issue with decreased speed, reliability or anything else.  And wifi made it super easy to move miners around the house (e.g. out of a guest bedroom if we had guests, etc). 

Bitmain, maybe you could offer the older controller board as an option for a few bucks more?