It's been discussed in other threads but it still bugs me that after all these years since X-10 was invented we still don't have a modern lighting protocol that could be said to be "ideal" for the DIY/retrofit market. As I go through the list of available options it seems like every single one of them has at least one fatal flaw that that makes it at best, a compromise solution. I have not tried every option available so feel free to correct me if I am misunderstanding something here but it seems like most of these problems could have been avoided:
X-10 - Slow and unreliable. Subject to false operation or blocked operation from noise on the power line. Whole house amplifiers can overcome weak signal issues but can't solve the problem of lights unintentionally triggering on from noise. Problems increase as you scale up a large installation.
Insteon - Huge address space designed into the protocol is completely wasted by the limitations of the PLM required to use it. The PLM has a link table that is too small, a processor that is too slow to read the table at a pace that keeps up with activity within the installation and the device has quality issues such as failing capacitors and a tendency to send false "all on" signals. Also the cleanup command designed into the protocol is uselessly slow and usually has to be aborted to process new activity on the line that occurs before the cleanup verification can be completed.
UPB - This would seem like the ideal protocol for retrofit with super strong power line signals that can travel for miles and cut through most interference and attenuation situations. Unfortunately the ideal retrofit protocol is packaged into devices that are about as far from retrofit as you can get. Instead of compact switches designed to fit into old work boxes overstuffed with brittle fabric cover wires from the 30s and 40s you get unnecessarily large industrial devices that look like they were designed to go into extra deep boxes in some commercial setting. I remember buying some PCS X-10 gear back in the day and struggling to find any location with enough box volume to actually install the things. UPB devices need to lose a full inch of depth to get anywhere close to being practical for retrofit in older houses.
Z-Wave - Suffers primarily from it's dependency on routing rather than "broadcast and repeat" to get a signal from controller to device. Supposed to be self-healing if a device in the chain fails or gets moved but stories I hear suggest that doesn't work all that smoothly. Also there are horror stories about how the routing can get hopelessly scrambled as you try to scale out beyond a certain size. Also the RF only signal does not do well in older houses with metal boxes and lathe and plaster walls. Also the early versions required you to take your controller within inches of an installed device to enroll it (can think of a lot of device locations where that would truly suck). Also early versions did no report status changes from local operation. Also, interoperability between brands is limited so key features might not work for you. Also the whole primary and secondary controller thing can get way too complicated and is another point of potential incompatibility between brands,
Zigbee - Most of the problems of Z-Wave but more proprietary and not really designed for DIY.
Caseta - Can only control scenes and automation from Pico remotes, not from the load switches themselves... WTF? How is this useful in any normal automation scenario?
RadioRA2 - Deliberately made difficult to access by DIY users. Lower RF frequency is better suited to the challenges of retrofit than 900M or 2.4K but still trying to push RF through metal boxes and lathe and plaster walls.
Wi-Fi - RF challenges in retrofit old work metal boxes. Mostly designed for app based remote control... nobody is really pursuing true DIY designs meant to work with an on-premise automation controller.
What am I missing that would point me to the perfect DIY/retrofit lighting protocol for the 21st century?