"Next Gen" is like an onion, it has many layers. On the surface, you have the physical layer, the Magic Bands and other RFID Media (Card Media, Key Fobs that the CM's use, and Vehicle media {like SunPass or EZtag}) These devices are attached to a UUID for a Guest. That UUID is what is used for all the other systems/databases that link you to the great hive mind that is
MDE. But each system appears to be a "silo" or independent system, with a common user front end. Right now, it appears that FP+ does not validate against the turnstiles. You just have to have valid park admission.It also appears that each kind of reader is tasked for a specific database/system. They do not dabble into the other databases. Here is a rough overview.
It also appears that each of these individual systems can bring down a part of MDE but not all of it. If all of MDE goes down then it has to do with the Front End Database or the Front End App/web GUI.
Because each system is independent, each system can have it's own failure. I think it the problem is with the individual applications and not the system as a whole. But, if one system, one very VISIBLE system is having problems (FP+) then the whole package is perceived by customers to be flawed. I think there are many great successes in their rollout, but FP+ should not have been rolled out widely until they had the software bugs worked out. I also think the bugs are more evident to the über Disney fans, like us.