DPDK is just a set of libraries for forwarding plane application development, so “introducing DPDK” actually means “writing a new forwarding plane”. What Vyatta really introduced is a pretty elaborate application based on DPDK that took substantial effort to develop (plans to develop it were first announced in 2012, you do the math ;)
So the real question is whether we are going to develop analogous application. The answer is “not yet”. If someone else makes it, we sure can look into joining the development and integrating it into VyOS, but I’m not aware of any projects that would do exactly that.
The other problem, especially with respect to DDoS, is that the only part that can be accelerated is simple L3 forwarding and stateless filtering. If a packet is subject to any intelligent processing, it hits the slow path and we are back to the topic of general CPU performance. Moreover, in systems that rely on hardware acceleration, lots of fast path and smart path intercommunication issues may occur (CEF = Customer Enragement Feature ;). Also, if intelligent processing is not needed, which is common for core routers in 3-tier networks, a fast but dumb L3 switch can be a better option in terms of performance and port density to cost ratio.
All in all, acceleration is a big and complex topics. Everyone who is interested is invited to join the discussion, but it’s unlikely VyOS will be able to provide it any soon.