To be clear, you mentioned:
- make and receive calls
- text messages
- a UI suitable for general phone use
- enough apps to be "good enough"
Whether the device will sport a UI that is suitable for general phone use is difficult to discuss because that's highly subjective. IMHO W10M had a UI that meets that requirement. When the device is folded, Andromeda's UI will be very similar to W10M's, which is why I'd say that bar is cleared.
Everything else, with the exception of "etc" ;-), has been commented on multiple times by WCentral and other sites. If there is something specific you want information on I'm sure I can dig something up, but you can probably find that yourself if you do some searching.
Your points are all high-level "asks". There is nothing detailed about them, which is why we don't need any in-depth details to answer them. That's also why we already know.
If it runs all the current UWPs on the store... isn't that "good enough" to start with? Isn't that 20x or so more than W10M has? Heck, just being able to run PWAs in Edge would open up many key apps plus the thousands of UWPs on the store not compiled for mobile. I can see a lot of people skipping their phone at that point.
Again, do you have any reason to think that Andromeda can't run standard UWPs?
First, you owe us a definition for "good enough". I'm going to assume you define "good enough" as:
"the ability to at least somewhat compete with the mobile app selection on iOS and Android".
Second, I don't know what your current understanding of UWP is, so I'm not sure if I can give you a succinct answer. Historically, WCentral has done a dismal job of explaining UWP (although they are getting better), so most people here have a dysfunctional understanding of what an UWP app actually is.
The short answer:
Yes, Andromeda will be able to run all apps in the Microsoft Store, that includes UWP apps, PWAs and Win32 apps that are distributed through the Store using the Win32 bridge, a.k.a. Centennial. It will also run all the Win32 software available outside the store. Unfortunately, using the definition stated above, that isn't even close to "good enough".
When the average smartphone user thinks "mobile apps", they are thinking of their favorite social media apps, their local grocery store, local event and local travel apps, payment apps and the mobile gaming fad of the hour. The Microsoft Store, even with PWAs, offers very few of those. Often none at all. The lack of those apps is precisely what constitutes the app gap. Nothing about that has changed. While a specific individual may get along fine with that selection, for the average smartphone user, no device can replace their smartphone if it can't provide similar functionality for those use cases.
Furthermore, whether the software library at your disposal is 20x larger than it was back in 2015 depends on how you count:
If you're counting all the Win32 software that an Andromeda device could potentially run (as mentioned above), then the offering is easily a hundred times larger. IMHO that's just irrelevant in terms of the devices ability to act as a smartphone replacement, because 99.9% of those apps can't run on small screens.
If you're counting only PWAs and UWP apps that have been explicitly designed to adapt to small screens, i.e. they have a touch optimized UI that can be displayed when the device is folded, then the Store contains far fewer apps then it did back in 2015.
Given this reality, I have no idea how you'd expect such a device to compete with the mobile app selection on iOS or Android.
On the other hand, if your looking at the app selection when used as a PC (unfolded), then you could say iOS and Android have a major productivity software gap. For people who are primarily looking for a smartphone that simply isn't relevant.