I think users are not interested in widgets and unite.
The newest opera unite application was realesed in may 2011 (http://unite.opera.com/application/722/) whereas there are new extensions everyday.
Of course, API is not updated (vide: http://www.opera.com/docs/apis/extensions/windowsandtabsguid...)
In my opinion, Opera focuses too much on creating new things instead of improving support, especially of google services (eg. G+)
We don't want Opera to stop innovating though. They seem (!) to have driven a lot of the innovations over the last decade that I've found useful.
FWIW I don't use Op on the desktop, primarily because I've become entrenched with FF since moving to it for web dev tools some time ago, but on phone and tablet I find Opera far better than other offerings.
Opera has always been wanting to do more with its product, and widgets and Unite are examples of this, not to mention the Opera Platform (a mobile phone UI implemented with HTML, CSS and JavaScript, that unfortunately never made it anywhere). Oh, and BitTorrent, which I just remembered, because you sure don't see it in the user interface anywhere.
You're not alone thinking Opera has focused too much on creating new things ... internally people have also been thinking and saying this. I remember people complained regularly about Opera crashing when I worked there, although I personally have never had much problems with stability.
The lack of polish on the desktop version could also be because they have been putting a lot more resources on the mobile version ... after all, they bring in a lot more money. Opera is also a lot more successful in the mobile market, as the original article mentions. Opera Mobile is a great product, and Opera Mini is just amazing.
Do you think if it is possible that Opera could do some cleanup of its product lines? There were some successful things, such as Opera Mail client. But there is a lot of unused gadgets.
It would be great if Opera had some statistics about usage of specific features. I personally don't know anyone using bittorent, widgets, unite.
(I'm from Poland, Opera is quite popular here)
There was a project on collecting usage statistics, but I don't know what the current status is, or how the data was used. I doubt the features you mention will disappear anytime soon, that would probably be seen as a little too drastic.
Opera probably still wants to push the browser as a platform, especially on devices (http://www.opera.com/business/devices/), and widgets and Unite are important for this.
FWIW I don't use Op on the desktop, primarily because I've become entrenched with FF since moving to it for web dev tools some time ago, but on phone and tablet I find Opera far better than other offerings.