I have also read a little more about FLARM.
It should be appreciated that it would seem its range may be less than two miles. This would partly make sense as you get nowt for nowt. One of the reasons transponders are "power hungry" is they generate a strong signal that is not prone to interferance. FLARM on the other hand relies on low power consumption.
According to the FAA it takes around 12 seconds from seeing another aircraft to avoiding it, so at GA v glider speeds FLARM gives a buffer that is marginal at best.
I think that is another reason why it is unlikely the CAA or EASA would ever "approve" FLARM in its present form.
If it could be done FLARM combined with PCAS would appear to have some benefits.