I’m puzzled by your question. Napster is one of many streaming services available, though of course there may be restrictions in some countries. And local media playing has also been supported for some while: use the Music Library facility to specify a computer or NAS holding your music files. 

I don’t believe Alexa integration was a gimmick- nor Google Assistant. I don’t really use them much other than for a convenient “volume up” type command from time to time. 
 

What improvements are you looking for, if you feel Alexa integration was an unnecessary gimmick? 

I’m not sure how Alexa integration could be considered a gimmick when most of the major music streaming services are supported on Alexa. Not to mention the ability to control smart home devices using your Alexa-enabled Sonos speaker.

What country do you live in? Napster on Alexa is currently only available in the U.S, Mexico, and Brazil.

Uk here and the gimmick in my eyes was the original idea that alexa enabled sonos devices would do so much. If you look back to when these devices were first sold, people in this forum asked for voice enabled local media playback, some of us asked if napster could be voice controlled, just like spotify. 

Sure, the devices can switch off the lights and remind me that the football is on the tv etc but some of us just want to listen to music and control it with our voice. Napster and local media files still cant be controlled that way, even after patiently waiting for many years. 

Whilst Napster Music and Local library files may not be supported by Alexa to actually ‘initiate’ playback selection, you can still load the tracks, albums or playlists to a Sonos queue manually …and then voice-control their playback with the Alexa Assistant, including changing volume/mute/skip/repeat stop/pause/play tracks etc.

Thanks but that is something which has been about since the start. My gripe is that years after people requesting things, they still seem to be overlooked. 

I like the fact i can skip songs which are in a locally stored queue but i would rather be able to tell the speaker to play a song which is in my library. I would also like to be able to control napster via voice in the same way. 

Well here’s hoping that one day it happens and you get what you wish for - the more features, the better it is for all users.

There may have been requests for further features at outset, but I don't recall Sonos giving any commitment to implementing these features.

But an important point to make here is that you cannot launch local music using Alexa on Sonos because you cannot do it on Alexa. Or Google Assistant for that matter. I don’t think this is under Sonos' control. 

Local music listening is increasingly a 'niche' activity on Sonos. I was disappointed when voice control of local library wasn't fully available at first. But now that lossless streaming is easily and cheaply available I am completely indifferent to local library control.

Sonos clearly abandoned development of local library functionality years ago. I wouldn't hold your breath waiting for this development. 

I believe Napster worked with Sonos on Sonos Radio HD, so maybe that ‘partnership’ will lead to something further, perhaps, like Alexa control of their service, but we all know these things are never announced in advance. It’s a case of having to wait and see what happens.

There’s also the case that Sonos acquired ‘snips’ voice services a while back, so maybe we might see something emerge from that too?

Development in big companies is pretty slow. We don’t know how much time it take to complete so untill know enjoy what we have .

I think have a tendency to over value certain features.  Yes, it may be very valuable to you, and you may have seen others post similar requests, but that doesn’t necessary translate to a feature that Sonos can and should implement.  For one thing, they have access to more objective marketing to say how really valuable a feature is.  They also have the ability to test a feature to see if it has the results we imagine it will.  Many features sound great and theory, but are lousy in reality.  As John pointed out, some features are out of Sonos control, or are much larger of a technical development cost than we imagine.  And of course, there are limited resources to develop features.

Personally, I think I’ve come to the conclusion that most of the features I want are not that practical or useful to people in general.  So I may ask, but have zero expectation that anything I look for will be developed.