Gee whizz ! I'm off to rest a bit... And I come back here to find this diary that would take pages to answer properly!!!
So I'll do it short :-)
Of course, I don't agree with the general direction of it, while I do agree on the "results" !
I feel there are several facts mixed up in some of those popular beliefs ( not to hurt anyones feeling, but, I do hear that often :-) )!

Chapter one:
First point: Has modernism (as a movement) killed roofs ? (I would say no)...
Second point : Does modernism (as a movement) still exist ? (I would also answer no)...

Chapter two:
First point: Who, today, decides of a building (look, shape, form, program, usefulness, performance, etc...) ? Certainly not the Architect, but either a jury (mostly political people) for public buildings, or the banker (hello Jérôme :-) ) for the private ones...!
Second point : Building costs have been reduced to a sheer minima. Contractors have eaten economically each other and are reduced to a handful that makes the "law" (or you don't have your building done!).

Chapter three:
First point: CADs and other nifty devices just don't really help, as most users don't even "see" in space. It's more about having the best "library", ending, of course to the "famed" boxes !
Second point : At IMAGINA in Cannes, at the end of january there will be a debate with Peï and Piano on the importance of line in architecture (le "trait" in french, which was the ancestor of the descriptive), and of course what it has become in computers!

Chapter four:
First point:  In a time where each beam is controlled six times by various people, the knowledge of structural engineering is truly very low. Most engineering offices can't even calculate a shell (they don't do it at school anymore), as such structures doesn't go in the structural program that knows only about porticos !
Second point : Most people (architects and engineers) often get mixed up with scale ! Think of the cable of the Golden Gate bridge... When there is wind and load (trucks) you can see it wobble as a mere string. But if I give you three meters of the same cable, you could use it as a post ...

Conclusion:
There are bad architects and bad architecture. I've fought against the glass/steel box design in countries that didn't even produce steel nor glass ! Each time such a design won the contest.. Because that's exactly what the client wanted.. A no-nonsense office building, showing wealth and swiss watch precision for a reasonable price!
Most want a Ferrari for the price of a Twingo, and they'll find someone to draw it (I don't say design!) and often don't even care if it will last long, or if will cost fortunes to tend.

There are exceptions, of course, but we are surrounded by buildings that carries no culture.
And that is only about buildings, now think a bit about urbanism, and who designs your future way of living in a city !!!
Sustainability, even if it is sometimes a trend, is a hope for many architects, as it allows for a better designing as for built materials.

About the skating ring catastrophe, I haven't seen the building before seeing the shambles on TV... I'm just surprised that the German rules on snow overload weren't applied. I think they were, and that the building had another structural failure (?) before giving in under the snow... I'll ask around !

Sigh.. And I thought I would "heat" a bit by lurking gently and lazily for the new year ! :-)

"What can I do, What can I write, Against the fall of Night". A.E. Housman