In principle, hiding a more efficient, stable, reliable, and (one would hope) long-lived modern power supply in the eviscerated carcass of the original unit (i.e., reusing the case), thus both preserving appearances and protecting the delicate vintage electronics in the actual laptop, would be a really good idea.
Unfortunately, as far as I can tell based on a very few reports by the presumably knowledgeable minority who regularly do real repair work on these things, the original design has held up fairly well over the decades, even in comparison to more recently designed units—which, one might have hoped, were put together with a better understanding of how to make them excel (apart from the need to recap them, of course). Thus, unless your vintage wall wart really is verging on irreparability, the most cost-effective course of action appears to be a simple recap and cleaning. (I would welcome corrections on this point from anyone with actual field experience in performing such repairs.)
I admit to having been somewhat annoyed about basic repairs being the most effective way forward save in extreme cases, considering how utterly undamaged and even pristine my dead PB 1xx supplies appear (which implies an irritatingly opaque and tedious diagnostic sequence in my future, should I wish to do a proper job of fixing them). Then I realized that it represents an entirely new (to me) aspect of our hobby to roll up my metaphorical sleeves and get stuck into, which I figure is very unlikely to be a truly bad thing when all is said and done.
