I appreciate your post, but I just need to get a couple of things straight:
We didn’t drop it because of his conviction of murder - actually, this technically does not really matter. In an open source project, we have code from thousands of people. Statistically some of them have committed crimes, but we cannot rip out everything those people wrote. Technology and those things don’t go together. I do of course not want to downplay at all what Hans Reiser did.
As Arne already said, Reiser4 was an amazing file system at that time. Robust and fast. What else do we want from a file system?
The biggest problem for us is, that it is being maintained out of tree. With every kernel update, we will have to wait until someone has ported Reiser4 and we rely on that patch being maintained for that release we are on.
In practise it hasn’t worked well for us to rely on other people like that (see grsecurity) and so I am not very tempted to merge another out-of-tree patch again.
Regarding Reiser5, I saw the announcement over a year ago. It is a bit sad, that they did not rename it to something more neutral to distance themselves more from Hans Reiser, but that is of course not my decision.
For political reasons, it will become quite hard again to get it merged into the mainline kernel I would predict. And secondly, it seems that the hunger for new file systems has disappeared. Underlying storage is fast enough that the FS usually isn’t the bottleneck any more. ext4 and XFS which I would regard as the most commonly used file systems are good enough for everybody.
ReiserFS is there for historic reasons. It is absolutely outdated, and again, nobody has requested more choice here in a while. I wouldn’t mind to drop support for it actually.