Some thoughts on Btrfs. Btrfs is still not completed and production ready. It's disk format might (and mostlikely will still) change in the future. So one has to take into account that maintenance will be required to keep the Haiku implementation in a working state. I think strategically, better (full?) support for EXT (in particular EXT4) would be more useful. I suspect that a sizeable number of Haiku adopters in the beginning will have a Linux background and therefore will want Haiku to cooperate as best as possible with Linux on their machines. FAT/NTFS support was a big deal for Linux back in the days. But nonetheless, the ACPI extensions sound like a really good idea too.