Rescaling often does, indeed, improve the tone because revelations in
string design have come to light (such as that providing more plain
wire between the end of bass string wrappings and their bridge helps),
because a piano scaled for A-435 may not sound as good at A-440 (if you
wish to tune it to such), and other factors.  Loose bridge pins and
collapsed soundboards should also be taken into consideration, though.

As per soundboards: interesting innovations in re-crowning them with
penetrating epoxy have been made, with reportedly fine results.  (For
those not interested in new board installations.  I am very much in
favor of keeping the old board, if possible.)

Talk to J.D. Grandt up in Canada about rescaling; he's knowledgeable
and affable.

Gordon Stelter
Athens, Georgia