There's a lot of misinformation and half-truths in this article. To pick one example, the filesystem: yes, we're sadly not using ZFS but that's in all likelihood due to licensing restrictions, not because Apple thinks HFS+ doesn't need replacing. What Apple has done is introduce CoreStorage, a "storage virtualisation system" (see link below), which beyond allowing new features to be added now (e.g. full disk encryption), will presumably allow easier migration to a new filesystem in future. And this was added in Lion.

http://blog.fosketts.net/2011/08/04/mac-osx-lion-corestorage...

As a self-described power user, I've found 10.8 to be a nice upgrade on 10.7 and worlds better than 10.6. That's not to say there aren't issues -- there are many, as there are with any OS -- but Apple currently isn't showing any sign of slowing down, with many of the issues I've experienced having been fixed in 10.8, while any power user is quite capable of disabling new consumer-facing features that don't benefit them (e.g. Launchpad, iCloud).

Edit: reading further, there's a better example -- the author's criticism of Fusion Drives. I quote "Bottom line: Fusion as-is and as supplied by Apple is OK (maybe, hard to say for sure in multi-drive systems). Other than that, messing around carries some ugly risks."

Not only are Apple's Fusion drives a new technology (and it's a relatively pioneering one at that, at least in the consumer space -- they're not HDDs with an SSD cache, but rather SSD/HDD hybrids that intelligently move data from one to the other), thus disproving the point that Apple isn't innovating on OS X anymore, but his criticisms apply when you're making your own Fusion drive, rather than buying a computer with a Fusion drive installed. This is something unsupported right now, especially since Fusion drives have only existed for several months, so although of course it should be fixed I don't think Apple deserves too much criticism for this.

Second edit: this is perhaps controversial, but I think it comes down to the difference between a power user and a dangerous user. Power users who have to get work done will generally stick to supported system configurations, or will be damn careful (and with full knowledge of what might happen if things go wrong) if doing anything unsupported. I don't think any "power user" would have a custom Fusion drive setup and then complain about Apple when something goes wrong. That's not to say all of the criticisms in the article are wrong, because they're not, and some are quite serious. But some things are definitely disingenuous too.