IMHO that is a debatable point. Certainly Apple has included the features it said would be included, but as to them really working in a practical sense, I would say not always. For example, it comes with a fitness app and has a HRM. That's fine for a long walk or if you run but don't really train to improve. Ultimately, it's a weak substitute for a dedicated fitness watch, one of the THE big market points of AW put out by Apple.
Another bone of contention is that while the AW works, it's rather slow. Launching an app isn't an "instant on" process. There is a short waiting time, something a device like a watch should not have because the whole point of using a smartwatch is to save time. But when you could pull out your phone and launch the app there before it surfaces on the watch, well...
The AW really reminds me of the first Newton. Amazingly cool idea, demo'd great... to the point I actually flew to Boston from DC on launch day to buy one. But the off demo use of the Newton was flawed and handwriting recognition to inaccurate for productive use. It was just not ready for consumer use at launch but then CEO John Sculley needed to prove his mettle with a new product. But it eventualy forced his leaving instead.
AW has lots of promise. I really enjoy notifications for example. But many of Apple's selling points are just that: marketing features that are not useful as designed. We'll see what performance improvements Watch 2.0 brings. But I think early adopters are being truthful in their complaints. Apple would have fared better underselling some of the features rather than unreasonably raising expectations of a supersmartwatch.
That is not to say there are some true Apple Haters that don't miss a chance to make pot shots. Those articles are there too. But look at what normally Apple friendly folks are saying. Buried in their general praise of AW are critiques of what AW doesn't do as advertised and what Apple needs to do to correct the issue.
I don't think they ever marketed it as a "dedicated fitness watch". The times when it's slow are pretty rare. Sometimes my phone and mac are slow too so. And then you ran out of examples - at bottom the occasional slowness is all you have mentioned.