Diesel emissions is still in a very early stage of development. Advancement in the electronics and new technology will help clean them up. For any of the old farts around here take a trip down memory lane and try to remember what the late 70's up through the 80's were like for emissions garbage on gas engines (car and truck). Miles upon miles of vacuum hose, EGR systems, AIR pumps, carbs with limited adjustments (or crappy basic computer controls), electronic ignition modules and pellet style catalytic converters. Remember how well those systems worked? They sucked! Folks were stripping them of the computer controlled carbs, EGR's and air pumps if they were in non-emission testing counties. Yes that was just as illegal then as this stuff is now.
Why I bring that dark time back into light is the OEM's figured it out. Technology improved and with more modern fuel injection systems and more precise computer controls for timing and fuel, the newer stuff ran cleaner without the EGR's and AIR pumps they once had. Look at any new gas powered truck and the only emissions components you'll see is the catalytic converters, EVAP system and PCV system. They run clean enough to not require the other crap. But looking at the modern V8's we have now in trucks we have more standard power than ever with better fuel economy than we did back then.
They are working on the technology now for sure as the emissions regs will continue to get tighter. We will probably see the same type of increase in power/economy with a reduction of emissions as they eliminate the need for some of the garbage by running cleaner to start with.