Hi, in relation to the points you raised:
1. The udev hook information and how it works is not a place for a bcache article, that is a part of udev. If you check similar udev functionality, such as that of the mdadm_udev hook RAID#Add_to_Kernel_Image you will see that these articles don't also copy a udev rule in to the wiki for no reason. If you think it may be best to put this back in we can, but I disagree and think that it does not belong there when it is a part of the package now, and the primary method to use the bcache hook. The original one was merely the loop to register all devices that existed at the time it is run. It was a time-sensitive hook in the boot process and I could not make it work at all; It *HAS* to run before filesystem, but putting it between block and filesystem hooks resulted in it running before block devices had fully initialized. The only way to have a functioning bcache device on boot is to use the udev hook. Perhaps we should have the explanation of the udev hook in the talk page? It seems to be a better place than on the main wiki page.
2. I added a section at the top for creating a bcache device as the old section was very long winded and targeted at a user following the installation guide but wanting a bcache root device. I left this in place and titled it as such (Installation to a bcache device) and created the section above it (Setting up a bcache device on an existing system) as these are the steps many users will want to follow if they already understand how to install the OS and just want the more diluted form. There is still a large amount of superfluous information in the installation section as it goes in to how to partition your drive and about making sure you have an EFI partition, and not to make a swap file on a btrfs partition; all of which are quite unrelated to creating a bcache device and are already covered in the installation guide. I didn't remove it as I didn't want to create a huge change. Most of the 1200 characters missing is from removing the udev rule and putting it in to the package.
3. I've fixed the reference to 'at every bootup' to be clearer and say that it will be required *unless* using the bcache_udev hook as it negates the need for it entirely.
4. I see on the discussion page that you were the one who wrote the udev rule that was included, I didn't see this the other day when I did a quick search for whoever wrote that section. I've added you as a contributor to the package. Thanks for writing it; it's the way it should have been done at the start in my opinion.
5. I do understand the material, I just missed one or two references to sections that I had changed. Old and outdated material should be deleted if we want to maintain the wiki in a useful form (have you seen the ubuntu wiki? everything from the past 5-7 years is covered in their articles and it is very hard to find anything useful). I would just like to keep the Arch wiki as up to date and informative as it always has been.
Let me know if the new changes are not up to scratch and I will try to make them better. I think the fixed references and that they now make sense.