It seems there are a pretty good deal of ideas for ever more sophisticated imaging technologies. That's nice. However it would be more reassuring to come up, at the same time (or in due course), with a similar supply of clever ideas for more sophisticated rocket engines, or, more likely, with a long series of fundamental contributions to our understanding of physics and biology. The ambition of the proposed mission is to reach a focal region ~548-900 AU away in order to image exoplanets which are distant up to 100 light years. I am sorry to have to remind us all about this, but given the extenuating long journey to reach a region that is not any closer than 548 AU, it would be even more "painful" to discover even more distant exoplanets which would remain beyond reach for all practical purposes – As per me discoveries of such level should remind us to reaffirm our commitment to take care of the only planet we can live for the foreseeable future.
Astronomy still provides useful insights regardless of whether we can reach those places or not.
That said, we are indeed researching ever more advanced propulsion technologies!
We've made great strides in electric propulsion, which is far more efficient for long voyages than chemical rockets. This tech is already in wide use today in satellites and probes of all kinds.
We're ramping up research in nuclear rocket propulsion again. There are several branches here: nuclear electric, nuclear thermal and nuclear pulse. Of these, the last one is the least developed since it basically means using nuclear explosions to boost you, but it has the most promise for futuristic spaceship drives.
There's also the possibility of using antimater pulse drives but that's a hairy can of worms. Very hard to produce the fuel in enough quantities.
