Elan,
I don't have the resources for the Terminator, but I do have a Denafrips Pontus II DAC. When I intially hooked it up to my old system using unbalanced Coax (no need to get into that), I too found the impact (attack) to be too laid back, soundstage was great width wise but not deep, and the highs were too laid back, a little sibilant, and treble to be slightly "veiled". I am using Buchardt Audio S400 MkII bookshelf speakers.
Since I was upgrading all of my components, I added a Denafrips Hades Pre-Amp and Thallo amplifier.....all of which are true balanced components. I hooked up the Pontus II to Hades Pre-Amp, and Hades Pre-Amp to Thallo amplifier with XLR balanced cables from Morrow Audio MA4 XLR cables....with 20 day burn in. I also swapped in Supra ethernet cables for the input to my Bluesound Node (3rd generation), and Supra USB from the Node to the Pontus II DAC.
Now since I changed so many components there, I am unsure which componenst/cables made the most difference......but that fixed most most of my issues. The attack was improved, highs were more detailed and I feel like the "veil" has been removed, and the soundstage was wider and now deeper than with my previous set up. Also separation were improved.
I am going to reverse engineer to find out which made the greatest difference, but I assume using the Morrow XLR cables, using a Denafrips balanced stack connected via XLR, and the addition of the Supra cables all had a combined effect in the sound improvement.