"Does it make a better bonsai?"
That's the big question. Undoubtedly, the needles would be smaller and the tree would look neater. But is that really the point of having an old collected specimen? It is only one definition of a "better bonsai."
Another definition might be that accepting the quirks of a species is part of the collecting game. You sometimes exchange long needles for rugged trunks, twisted branching that can't be reproduced, or some other feature that draws you to the tree.
I have a 200 year old live oak bonsai whose leaves are a bit on the large side (but not in the ridiculous range), it produces acorns that are out of scale, but I would not graft cork oak foliage onto it. It is authentic as it is, has survived too long for me to insult it by attaching alien leaves to it.
