Del has the solution right there
Lego manages to achieve pretty good alignment with little effort because of the interlocking pegs. Sun should adopt the same idea and stop making their chips flat, the pegs will help guide alignment.
Such pegs could even work as connecting pins and form the electrical contacts, with a better surface area to volume of metal than a flat surface contact it will reduce resistance/capacitance problems and so the heat requirements as highlighted in this article.