I agree that the rouge is holding you back. Since the IO is designed to drive a linestage directly, you can use a passive volume control like the Placette and get a huge improvement. I used mine this way and it was very nice.
You could also send your IO in and get the stepped attenuator volume controls installed. You save on interconnects and probably get the best sound but the disadvantage is no remote.
You could also send your IO in and get the stepped attenuator volume controls installed. You save on interconnects and probably get the best sound but the disadvantage is no remote.