I see what I believe to be a little bit of misinformation/misunderstanding in this thread. DPF/regens are to take care of the particles/soot from the diesel fuel burn. The use of DEF fluid or EGR, depending on manufacturer design, is to clean up the NOx emissions. Different techniques to clean up different emission "issues".
Effectively cleaning a DPF depends on the filter design, some are designed to be cleaned, others are almost impossible. There are shops around now to clean up DPF's for the truckers as apparently most of theirs are designed to be cleaned. Some car folks have sent theirs in to be cleaned and have been told that due to the design of their DPF... they can't be reliably cleaned. Due to EPA regulations, OEM's don't have much choice but to use DEF's to clean up the soot. The more HP an engine produces, the more the need for DEF. Hopefully soon somebody will find a better way around this issue, but until then... we are stuck with them.
My 2012 VW TDI uses EGR, DPF w/regens and DEF fluid, I like how clean and smell free the car runs. I had to replace a part in the exhaust that had about 65K miles on it... I was surprised to find virtually no soot on that part at all after all those miles. My issue with the new systems is how expensive replacing parts in the emission systems is.