KDE4 seems to have suffered a lot from people complaining that it's not an easy upgrade from KDE3, and to a certain extent, the complaint is justified. When KDE4 first arrives on the scene, it was really little more than a tech demo, and certainly not usable by normal users (I use the term "normal" users with all due respect - "normal" in this context means users not in the KDE development scene, and perhaps not as technically literate as the developers). However, the hype surrounding it's release meant that lots of normal users upgraded and were subsequently disappointed. With KDE4.2, we're finally getting to a stage where the KDE 4 series is actually usable as a desktop environment.
I am in a small team where we provide a Linux Terminal Server (LTS) for a company. It is based on NX. Every employee in this company can use the service, however, we provide it free of charge and out of enthusiasm. That means, we are not paid for setting it up nor for giving phone-support. We sometimes have 70 concurrent users on the server, that may mean we reach 500 users on the whole. The server is running KDE 3.5 as desktop environment. Recently, we evaluated - no, let me keep this understandable - we sat together and discussed the possibility of upgrading to KDE 4.
Everyone including me was against the upgrade. This is especially ashaming for me as I am spending every weekend to develop KDE. So what were the reasons?
However, that's still not answering the original concern: KDE4 is still not a replacement for KDE3. Tstaerk goes on to list some of the shortcomings he sees in KDE4:
Does he have a point? Perhaps.
If you install a KDE 4 desktop by default, you do not have the possibility to add icons to your desktop by right-clicking onto the desktop. That would mean to us: Take 500 phone calls, explain users why it is no longer possible, explain 500 times why we do a change if it is a change to the worse... You got it, 500 times an ENOTAMUSED.
If you install a KDE 4 desktop by default, you do not have the possibility to move the clock in the panel. For me, the clock is ticking constantly on the left where I do not want it. Our users will be upset seeing another change to the worse. Yes, there is a work-around but it is so complicated that I do not want to tell it 500 times on the phone
If you install a KDE 4 desktop by default, you get a strange icon in the upper right corner. No one could explain to me what it is called, but everybody said it was something about Plasma. Users will click on it and eventually hit "Zoom out". Then, their screen is filled with strange gray squares. Just imagine you have to sit on a phone and answer 500 phone calls (for no money) from users who all tell you something about "squares" not knowing they should call it "activities".
In some ways, calling the new product KDE4 implies an easy upgrade path from KDE3, which is misleading, since many aspects of the product have been written from scratch, and behave in a totally different manner. It would have been a better decision, I think to brand KDE4 in such a way that it was obvious that it was a new product, that would not work in the same way. This in turn might have saved a considerable amount of grief when developers found that their snazzy new technologies were being ignored, since users could not use the product like they were used to.
So, the moral of the story?
Be careful how you brand your product, especially when a newer version breaks compatibility with an older version. Is it an upgrade, or a new entity in it's own right?