Honestly, SRAM bits per square mm seems like a perfectly fine metric for me. While I recognize that the memory-to-logic density varies, sometimes significantly,

Honestly, SRAM bits per square mm seems like a perfectly fine metric for me. While I recognize that the memory-to-logic density varies, sometimes significantly, between processes, (a) SRAM cells are optimized to within an inch of their lives ("within a nm of their lives"?), including often being revised in minor process updates, so accurately reflect the capabilities of the process; (b) many chips, including the ones I personally tend to be interested in (processors, etc) are SRAM-heavy, and get more so each generation; (c) it's a single number with some connection to reality, which is better than both a single number with limited connection to reality ("process"), or a whole suite of numbers that require deep interpretation (cell library metrics).