Speaker suggestion for McCormack DNA 225 DLX

I can't seem to enjoy the sweetness of the Mccormack with my Martin Logan SL3's. I have tried re-positioning the speakers to every possible combination--and still frustrating. The sound is thin (although detailed), soundstaging is confusing and there is something lacking.

From your experience what speakers would you think would match the Maccormack amp?

Thanks.