UPDATE: Got my replacement phone a week ago. I had the well documented problems with my WiFi, then problems making calls necessitating its replacement after only 2 months of ownership.
I am pleased to report a MUCH improved experience with WiFi with the replacement. Accessing WiFi at multiple places (other than my home router which was never an issue), is now easier and the phone seems to maintain the WiFi connection most of the time. That's not to say that there are not delays getting on, specifically signing on, to the WiFi connection. On one occasion, at one facility, it took 15 min. to establish a successful WiFi connection.
In conclusion, this replacement phone is much more WiFi friendly than the first S4 I had, but you still need to still "jump through some hoops" to utilize WiFi at multiple locations.