Depends on whether that stuff represents everything that encompasses the needs of advanced users or users with advanced needs. I have VPN servers running on two of the routers that are in different locations, and they are setup for LAN bridging on stock firmware. The two AC86Us I have at my home are setup to run in Main+AP mode to provide full 5 GHz coverage across my house. I do actually have a USB network drive set up on my router at my cabin. Having said that, most people are aware that some aspects of the ASUS firmware are problematic. Their QoS implementation is poor, AiProtection is problematic in the current firmware, the Network map sorta works, the USB hard drive implementation is slow, AiMesh is a kludge. So maybe I'm lucky that I don't see a need for those features, or at least their performance is sufficient for my needs.
andyman's situation is unfortunate. I suppose his choices are to try to pinpoint the feature or features causing problems, go back to an earlier firmware, or switch brands, all of which represent time that could be spent doing something more useful.