Wrong blame. The trouble is not EASA, but Garmin aiming for an EASA STC standalone, which requires a different testing and documentation to the US EAA initiatives. The grandfathering rights to get through the FAA process are not easily transferable for a good reason!
Does it have to be GFC500? The competion is no problem to get legally installed at EASA registered aircraft for quite a longer time. I know of several flying the new autopilots for two years now and they started the same time or very short after as the US installations.