Building a new version of MDBT42Q with different libraries.

One potential problem (why I didn't use it by default) is there's hardware bug which means that 1 byte SPI transfers fail

There's another gotcha with nRF52 EasyDMA that I find annoying, the count on the SPI transfers is 8 bits which means that you can only transfer a maximum of 255 bytes, creating a really cumbersome sequence if you're transferring to/from something that has fixed 256 byte pages (like Flash memory to take a random example). You essentially have to transfer twice as many blocks for each page (transferring in 128 byte blocks, is the most efficient).

While concurrent SPI might be nirvana, there is a slight advantage to having muliple SPI ports if you're trying to lay out a tight board with multiple SPI devices. It's very easy to assign unique SPI pins to each device to simplify board routing. While the reconfigure-ability of the nRF52 pins doesn't REQUIRE you to use different SPI peripherals, using multiple peripherals does reduce the amount of reconfiguration necessary. I'll concede that this advantage, of course, is meaningless to an existing Espruino board, however.