Best amp for natural timbre of unamplified acoustic instruments & vocals w/ Revel F32?

Maplegrovemusic,
Yes I would find it hard to believe that a speaker would be intentionally designed to sound as described. On an open forum we can only respond to the information provided. If the OP has determined the speaker is the weak link then it's reasonable to suggest that another speaker may likely improve his situation. It could certainly be the fault of another system component or issue,  it also could be the speaker as the OP suspects. I do hope that he solves the problem to his satisfaction. 
Charles, 

I agree with the comments of John and Bill. If you find your speakers to have the intrinsic sonic signature you described (hard, thin ànd sterile) why keep them? Or to put it another way what are their attributes that would persuade you to keep them?
Charles,

I don't understand how you conclude that the F32 is the more "neutral" speaker when you've identified it as sounding hard, thin and sterile.  That doesn't fit the definition on neutral. Rather it would seem that the F32 has glaring inherent sonic flaws. Neutral implies absence  (or certainly less) of contributing sonic characteristics. Neutrality is synontomous with chameleon like nature. 
Charles,