My opinion on this is that the kernel should be the ground on which userspace should always work.
Features should be taken out with bug reports demonstrating breakage in general usage, slowdowns or security risks.
Another important point of view should be the maintenance required to support these seldom used features and I have nothing to comment on this.
Specifically regarding slowdowns, my layman opinion on this is that
On Thursday, March 27, 2014 04:45:24 PM Arthur Țițeică wrote: they are
meaningless in the general usage of the -ARCH kernel.
If taking out theoretically useful features out of the kernel means that in the end we gain 2 Mb of free memory or Apache is able to sustain 10500 connections instead of 10000 I personally don't see it as good bargain.
This seems like it doesn't exactly fit with the Arch Way though. Arch is supposed to be simple and minimal. Why should the default be "add all the features" for a distribution that is partially based on being minimal and lightweight? I guess I just don't see the reason for adding in feature by default that so few people will actually use. And the people who will be using it should have the knowledge and ability to build their own kernel that will have those features enabled.