This will be a huge change for people who wants to have dual booting, like the classic Manjaro/Windows dual boot. This is not really a bug in itself, as it is intentionally disabled and not by accident because of a programming error, but this choice means that people won’t be able to boot Windows from GRUB, which is something that we were usually able to do on Manjaro and with Linux OS in general and somehow has become the “de facto” standard in term of behavior.
Manjaro will most likely suffer from this choice for a time, and I do expect a lot of complains from the users, outcrying that “MY DUAL BOOT IS BROKEN CAN’T BOOT TO WINDOWS” or even worse, “OH MY GOD MANJARO DELETED WINDOWS HOLY CRAP” simply because they can’t see Windows in GRUB anymore.
Plus, any new user trying to do a dual boot will have an unpleasant surprise that they have to change the configuration of GRUB in order to have access to GRUB inside Windows, and I am afraid that Manjaro will be compared to Ubuntu, Linux Mint, etc., where it still works as it used to be (although there is no guarantee that it won’t change in the future).
For people that use UEFI, you can still boot Windows manually by selecting it in the boot override menu or whatever, although it is much less convenient than selecting it from GRUB I suppose.
I know it has been disabled for security reasons. But disabling it is not without consequence. Hopefully users will be able to accept this new reality. I would understand if Manjaro devs revert their decision for the sake of convenience and user-friendliness though.
Of course, people that use Manjaro as their only operating system has nothing to fear from this change, obviously.
EDIT: Just noticed that it was already a thing in Stable, which would explain (partly perhaps) the relatively bad result in the pool. My bad.