Replacing metal could be a very big deal too. Chips are mostly power-limited these days; slashing the resistance of the metal layers would be a big active power

Replacing metal could be a very big deal too. Chips are mostly power-limited these days; slashing the resistance of the metal layers would be a big active power win. In fact, while it would not help leakage (which constrains how many transistors you can pack in), improving active power consumption could correlate directly to improvements in operating frequency...