Given that SUSE originally used a highly customised KDE as its desktop environment, will it go back to this again?
There is no need to "go back to KDE", since we always shipped it :)
One of the things I like most about Linux is that it gives you choice. I have been using at least half a dozen of different desktops in the last years; right now I'm using xfce on my main workstations while my "family machines" continue to run KDE. My wife and children are just users and I think KDE still is the most user friendly interface. The main complaint I have about KDE is that it sometimes starts to be a bit over-engineered; I would prefer it to be less resource hungry.
Any commercial GNU/Linux distribution that is successful these days has to sell on its own unique features, not the operating system alone. One of SUSE's unique features is the SUSE Studio. Can you explain how this came about - the thinking behind it and why you feel it has been so successful?
(The) main driving force is probably virtualisation. In the past, you dealt with specific applications, nowadays you juggle with complete virtual machines. This has all sorts of advantages: the systems are separated; you have less security issues, need less hardware for testing, and can simulate complex network setups with just one big machine.
And SUSE Studio lets you create your specific virtual machine(s) easily in some minutes. It's so convenient. I used a Studio created appliance as starting point for my video disk recording system.
Any plans of taking SUSE down the mobile/tablet route?
Not to my knowledge. This niche has been successfully occupied by Google with its Android system. But personally, I think it would be fun to hack on such a system; if I were (had been) born 20 years later, this certainly would be my favorite playground now :)
What is the degree of coordination that exists between SUSE and openSUSE?
Very high! Mentally, most engineers do not distinguish between the two systems. It's just SUSE with openSUSE being the head branch and SUSE Linux Enterprise being the stable branch.
How do changes from the community distro flow into the enterprise distro?
Whenever something is changed/developed in openSUSE, people are pondering if and when this change should also go into SUSE Linux Enterprise. Sometimes those decisions are very hard since there are a lot more things to be considered: What is the impact on existing installations? How much effort is it to support the feature for many years? And so on. If some decision turns out to be suboptimal, it can be reverted relatively easily in openSUSE. In SUSE Linux Enterprise, we have to live with the results for many, many years.
Well, and don't forget the other way round - this also happens: often there are open source projects and technologies that are kind of "sponsored" or pushed into the openSUSE project on behalf of SUSE Linux Enterprise because we understand our customers want to have that specific technology incorporated. One example of such a technology is snapper.