Here's what's up -- lack of significant advancements in CPU technology is a real restriction. There just isn't much to do other than add more cores, and all those cores are hot, which then comes at the expense of clock speed. It's a tricky balance.
In light of that, Apple's decided that the big leap forward in the new generation of Mac Pros will come from the GPU side. Geekbench is a CPU-only test, so you're not seeing the important part. The important part is that on a GPU test it would obliterate any out of the box mac ever, probably by an order of magnitude. From here on out, it's all eggs in the GPU basket.
If the software creators don't take advantage of the dual workstation GPUs, it won't do anyone any good. If they do, then it'll make this new Mac Pro wipe the floor with the old model in real world use (not Geekbench).
Of course, you can always add GPUs to the old model. But it's the change in philosophy that I'm commenting on.