To be honest I don't think many people need high performance machines for software development anymore; I bought my PowerMac G5 and later my current Mac Pro because I did a lot of C/C++ development with complex projects that needed a machine with a lot of clout to be able to compile them quickly.The nMP seems to have impressive performance with FCP, but so far we haven't seen much written about its performance in other fields, in particular software development.
However, compilers have improved a great deal to the point that I'm not sure there are many software development projects out there anymore that really need to compile the whole thing from scratch anymore. I suppose in theory OpenCL could be used for that purpose, but I'm not sure it's an area that needs the best possible performance anymore. Really the main hardware requirements are dependent on what your end product will be; for example if you're building a game then you may need a good graphics card, or if you're working on professional video editing software then you'll need the kind of machine that might actually run that, but even then you may be better throwing together a cheap test PC for that kind of thing (assuming your software will run on it).
For example, in my own case what I do is mostly programming, so my next computer purchase is more likely to be a Mac Mini, even though I'd love a new Mac Pro, as the Mac Mini is plenty powerful enough for programming work (even so I'll wait for the next update first).
Probably not; I don't believe any of these uses will use OpenCL to run commands, in fact most server farms running this kind of software are now more likely to use machines with tons of relatively low powered ARM processors instead and/or lots of machines. So IMO there isn't really a desktop that's optimal for that kind of thing anymore, plus if you're just mostly doing testing it's something that a Mac Mini or iMac should be more than capable of handling as they have enough cores/threads to show how well your parallel components run.I've been trying to compare it to other desktops, workstations & servers for running Java application servers, databases, assorted VMs and Java-based development environments, but haven't arrived at a conclusion as to whether the nMP is a good fit.
Hell, I have several Java programs plus a database and DNS server running on a Synology DS212j (NAS) and it has, iirc, a 1.6ghz single-core ARM processor and 256mb of RAM, and when I was still using a G3 iMac I had a web-server and MySQL database running on it for testing; unless you're doing something that requires a lot of parallelism and or brute power then pretty much any modern machine should be plenty.
So yeah if it weren't for the fact that I enjoy also do quite a bit of video transcoding, and like to do gaming from time to time as well, then I'm not sure I'd even seriously consider a new Mac Pro at all, other than from the "wow I want one" perspective. Right now I'm waiting to see what the next Mac Mini update looks like as that'll determine whether I get a current Mac Mini cheaply, or a new Mac Mini, though there's still the possibility I'll buy a new Mac Pro anyway because I'm terrible with my money