I agree this is frustrating -- I was really happy to have the WR902AC running on a snapshot and was looking forward to it being supported in a future stable release. I honestly would like to say a big "thank you!" to the developer(s) who made this possible initially, and I am hoping that there is a not-too-painful way to re-add support for this device.
I'll admit that I am coming from a tech-savvy but non-developer perspective, but I am really curious about something... The TL-MR3020 (4MB flash + 32MB RAM) is still supported in the snapshot and latest stable release (17.01.4), while the TL-WR902AC (8MB flash + 64MB RAM) is suddenly not supported anymore based on the kernel being too large. Why is this? If a standard image including LuCI can fit on the MR3020, why is there an issue with the WR902AC which has twice the memory?
Also, if it turns out that there are problems resolving the memory constraints for the standard support model, can the WR902AC at least be supported in the image builder -- this would allow customized images like what I've been doing for the MR3020 which also fits within the 4MB limit (standard image, less LuCI, and added support for USB and storage/file system stuff such that the extroot process can be done).