Chips can fail in a number of different way. There is simply no binary state for this (1 for working, 0 for not working). For instance, chip can give out same amount of hashes therefore showing similar heat signature, but producing only invalid shares? I don't have access nor funds to get high-res thermal camera!

I'd like to see small LED right next to the chip that shows it's logical state, LED should be controlled by software and used as ID when you looking for it. A couple of control points, like ones on Raspberry Pi right next to each chip is another good idea.

Socket mount approach also sounds very good. That would save a lot of time looking for qualified tech in the area (I recently had control board repaired on my HVAC unit, a tech claimed he had 30 years of experience of repairing PCBs; He could f%ck up a cup of coffee - how skilled he was). Yes, it will add cost in the beginning, but it has a potential of home replacements in the future.

Holes for heatsinks mount, 2 per each group of 4 chips would be another thing - what if you want to overclock the chips assuming you can deal with heat? Talking about overclocking, there is got to be proper power reserve on board for this purpose.