It sounds like the author simply doesn't like change and is looking for things to pick apart. Yosemite is faster on every machine I've installed it on and I think the new interface is a new, modern, fresh take on OS X. If it's slow or dropping frames, perhaps it would be best to investigate and diagnose if your machine is OK or not before complaining. Of course, interface preference is subjective but I suspect most people simply don't care that much.
Change is hard, but if you go into it with this attitude you won't ever want to upgrade or try anything new.
Some interesting points but I personally don't agree with most of them.
Time machine, I personally hated the previous interface. Always felt it was clunky and slow.
Icons are pretty poor but they are so small on my screen it's something I can live with.
The font! Oh where to begin, after using this font for hours on end now I thought I would have got use to it, but something just isn't quite right with it!
* beginning of wine-fueled rant *
Overall I personally am still in a mixed opinion on Yosemite, it took almost 2 days to get my work machines (iMac 2011 and rMBP 2014) back into a usable state.
Almost everything was broken, network drivers (I use 10GbE), my IDE, VM environments, file sync, backups.
But worse of all they seem to have changed the mouse acceleration settings! As a long time suffer of RSI/Carpal Tunnel Syndrome I have learnt to manage it so well that most of the time I forget I even suffer with this.
One of the best ways for me to manage it was to purchase a Razer Mamba mouse, which worked flawlessly in Mavericks. Installed Yosemite and the mouse was unusable even on the mouses slowest setting, tried another mouse, same issue. Completely unusable!
After spending hours upon hours searching for a solution and setting my RSI off to levels which I couldn't sleep for 2 days! I finally found the USBOverdrive app which lets me control the accelerations to something which matches Mavericks.
One week later I am still suffering with pretty bad pain in my wrist!
I'm not sure how "Popularity" counts as a reason unless you are a high school student. Also, on my i7 MBP Retina with only 8GB RAM / 256GB SSD I notice no lag whatsoever, even while running a VM and two browsers. This strikes me as an extremely long-winded whine, similar to what you hear when Facebook makes any UI changes. Revert then, and be done with it.
Agreed with some respects (lack of contrast, saturation choices, and so on). I have trouble telling the difference between something I'm just not used to, and something that will be changed in either 10.11.0 or 10.10.2.
That said I already prefer Yosemite overall to Mavericks and wouldn't go back.
Other criticisms I can't agree with. The removal of the starry background in Time Machine? Calendar icon being too thin? (agreed on Mail's icon though).
With those cosmetics out of the way, we come to the performance section. I'm just not seeing it, on a 2012 Macbook Air (I think this should count as a middle-of-the-road performer in the Mac lineup). I suspect there's something wrong with the graphics driver with respect to the writer's hardware.
DWD's Design inspired by Yosemite? Please. They're trying to add a way to implement similar features that Gnome 3's header bars offer in their paradigm for rendering window decorations. (https://help.gnome.org/misc/release-notes/3.10/#header-bars). The flat design sense also seems to be partially inspired by android holo, the current KDE "oxygen" design, some of gnome 3's design, and in general, flat design is more popular these days.
Wow this is crazy, I have had the exact opposite experience with Yosemite. It's faster, much better looking, and finally removes some of the horrible skeuomorphic warts that had been on the OS for a long time.
I've noticed no lag either. However I see the same black box around the Volume animation popup. I just felt Apple sucked there - a company that I loved for design and for details making such a mistake?
Adding to that, I've owned two Mac's over a period of 3+ years and never once have they crashed. But today Yosemite just shut down all of a sudden. I've lost my confidence on Yosemite.
Interesting to hear your opinions about Yosemite.
Yesterday I had a conversation with an apple employee and he also confirmed that they are aware of the UI performance problems. I expect apple to fix this soon.
Change is hard, but if you go into it with this attitude you won't ever want to upgrade or try anything new.