Right, with the release of a new Fenix 5 model I'm posting in hopes that we persuade Garmin to take the time to produce a mount for the Fenix 5 which is quarter turn mount based.
With the introduction of "Quick Fit" bands and the tiny retention mechanism, I'm certain it's possible to incorporate them into a moulded block of plastic with a quarter turn attachment.
As a means to an end, I've sketched the design on post-it: Garmin, please feel free to use...
Ultimately, this product is already offered for other versions of wristwatches, including the very similar Forerunner 935 - unfortunately listed as Fenix 5 incompatible.
https://buy.garmin.com/en-GB/GB/p/557702
Please find the time to submit an idea submission to Garmin, as the more demand, the more chance this will ever happen.
https://www8.garmin.com/contactUs/ideas/
Also, I've purchased the watch mount, but it looks silly on my bars, take up too much space, causes trouble with cables and is a fairly silly (non-pro) looking solution.
https://buy.garmin.com/en-GB/GB/p/11078
Meanwhile, keep it rouleur,
Levi