It is worthless to support a standard that nobody implements.You're out of your mind. Using your logic, there is no value in supporting any new standard, because at that point nobody has implemented it yet.
ACPI is a usable and solid platform; unfortunately it just so happens that the only vendor who embraced it from the very beginning has done a bang-up job of, well, banging it up. Netscape did a great job pissing all over HTML in the old days, and Microsoft followed them by pissing all over DOM and CSS. Does this mean that nobody should bother doing things the right way? How is progress made if everyone just follows the leader?
The linux ACPI project needs to figure out how Windows manages to work reliably and emulate that<sarcasm>Sure, because reverse engineering a binary-only operating system is obviously the most efficient way for people interested in ACPI to spend their time.</sarcasm>
Anyway, this isn't an issue of "reliability". With few exceptions, the ACPI code works fine if your machine isn't broken. I run at least 10 desktop systems in ACPI mode and never have any ACPI-related trouble.