The reason for the delay (this time) is that FUSE has had to be adopted (with the blessing of the FUSE team, I might add - I'm a personal friend of the principle author) into a system that can barely handle it.
The ARM inside the Vega and Vega+ runs at around 400MHz. Originally, there was a bare-metal emulation in the Vega which just about managed to get a decent amount of compatibility without having to sacrifice speed. Emulating a spectrum is not a trivial task when you try to get as close to 100% accuracy as current knowledge allows - you'll need around 350MHz to do it on an x86. That doesn't leave a lot of room for OS overheads, so the Vega sacrified the OS entirely.
Unfortunately, one of the chaps who has left (initially to fund their own device, "the64" which crashed and burned) took his emulation with him, so the RCL team - in something of a hurry - decided to take the open-source FUSE and use that. Unfortunately it needs a Linux OS to run on, and they don't have one. So modifying FUSE to run on the Vega is taking some time.
That article states that the FUSE team have distanced themselves from the Vega, which simply isn't true. When questioned, the FUSE team shrugged and said "It's open source, who gives a toss what they do with it?" (or words to that effect).
As well as the FUSE woes, the team are also fighting legal battles against the two directors who quit - and left things in quite a mess... I was one of the people who helped to recover RCL's we presence from archive.org because the files supplied by one of the departing directors was unusable, and there have been rumours that it was deliberately so.
