I'm sure you'll be pleased with the D2000s - based on the fact they seem to be very similar to the D5000, and I'm very happy with mine. You will definitely have more bass than with the K701s - the D5000 has a good deep bass for headphones, but not at the expense of the rest of the sound.
I've still got the standard (for the Caiman) lm4562s in, and I don't feel any need to replace them - the D5000s and the Caiman seem to be made for each other ... at least to my ears Hope you have fun with them!
Simon