I think the HCW will be the way to go in general. That's not to say that a coin cell should use that, I would opt for the CW for that.
The W/HW format is unnecessarily large and complicates matters for me.
I am optimizing to support the HCW/CW on all motes (except a coin cell mote which will only support the CW). It will take a while. There is now the R5 which takes the HCW footprint only, the next revision will take both HCW/CW.
RE the heat test, if this is to be bootstrapped, i think it should work across all motes, with any antenna or without, and with any battery or power option. Otherwise we either have different pieces of code depending on hardware configuration, and then it's more complicated than just using the #IS_RFM69HW and it obsoletes this method.
IOW this code has to just work regardless of anything.
But I believe that short of having a hardware indicator, this is a very good solution. The only better thing than this is having a logic pin on the RFM69 itself. That's another discussion perhaps - but my thought on that is that we know that the HCW/LoRa footprint will always take a 20dBm radio, whereas the CW footprint will be a 13dBm or a RFM12B. So.. the Moteino itself could implement this on its own - it could be as easy as a solder jumper - the only problem is it would still require user intervention.