I completely agree with fdalbor.
I have the Lumia 820. Whilst I would like it to have the 920 camera and gorilla glass (and an HDMI out would have been great, so I could watch videos on hotel TVs), I needed the memory card capacity and the wireless-charging back (NOT a cover), so the 820 was the better choice for me, personally (more so because of the removable battery). However, if my 820 is lost or destroyed (and I ask this of 920 owners, too...who are happy enough with the 32GB capacity), with what would you replace it? It seems to me that Nokia has offered no reasonable or acceptable alternatives to either. Of course, we can all think of 'upgrades' we would add to our 820 or 920; but, failing that, I would at least like to get something 'as good'.
The 925, with 16GB and no SD card or wireless charging, without an ugly cover added? The 1020, with a lump on the back and no wireless charging without an even more cumbersome cover (and still not enough memory for me)? As for the 1520, wonderful spec, but its far too large...yet is probably the only Lumia I could even consider, since my minimum requirements are Here Drive+ (preferably free) and 64GB of storage (I assume this has wireless charging due to the accessories available, but can't see reference to it in the Nokia website spec?).
It seems to me that Nokia (and WP8 in general) needs to get a bigger share of the market so that the apps everyone wants are forthcoming more quickly. If not for that point, I think WP8 phones are wonderful and superior, in many respects (for my needs, at least). However, surely the best way to accomplish that will be to retain existing users and add more. Simply alienating the existing converts and trying to start again, every time you add a new phone, seems a flawed strategy, to me.
Bring out a 920s, with an SD card slot (and, ideally, a removeable battery, but not as essential for me), and I think you retain most of your existing 820 and 920 users for some time to come. For all those that require the other models, great; they will add to your client list. As it stands, I really dread the demise of my 820 and, worse still for Nokia (I would have thought), will retain it for as long as technologically possible, unless a true and appealing alternative is provided.
I appreciate this is a personal view, based on my own needs, but I'm afraid those are the ones I tend to spend most time considering. That said, those here who are perfectly happy with their 820 or 920 will, I suspect, tend to agree with this view.