It's not a system I'd usually expect to sound bright: is this with particular recordings, or with everything?
The only obvious change would be an interconnect capable of more solid bass: Chord Chameleon Silver Plus, at about £100 for a metre pair, would be a good starting point, IMHO, but you might want to look further up the range for a good match with the MFs - I think Chorus 2 would be even better.