I agree with having drivers redone to maintain balance left to right. Even though the foam isn't deteriorated it is not as firm as it once was dramatically affecting the ease of excursion and overall sound character.
if one midrange needs a new foam surround, should
they all be done, on the theory that if the foam of one has deteriorated, the are all probably in similar shape? there are 4 (d'appolito array) in my 14-year-old speakers.