There's only 19 games played and we are only in febuary. This isnt a big enough sample size.
in regards to your question.
1.I went through about 7 of the games and i think only 2 shared a somewhat similar line, most of them were completely different.So no, the semi-slav and orthodox QGD (which some transposed into) have NOT been busted.
2.Below top level (none GM, which many of the players on that list were not) the semi-slav is maybe a bit less popular, black can't really forcehis way into the semi-slav and white has a large amount of options to choose from, which drives players away.
Comparitively, black can force a sicilian on his opponent, and will usually be able to get a Najdorf, since whites options other than the open sicilian arnt all too good.
Looking at chessgames.com, I see that so far, only 19 Semi-Slav games have been played so far this year. (In comparison, there has been 53 Sicilian Najdorf games so far.) Black won in only one game. The others were all loses for Black or draws.
(http://www.chessgames.com/perl/chess.pl?yearcomp=exactly&year=2014&playercomp=either&pid=&player=&pid2=&player2=&movescomp=exactly&moves=&opening=D43-D49&eco=&result=)
Is the Semi-Slav in trouble, theoretically? If so, in what way (i.e. is a particular line troublesome or is the opening just unsound in general)? And could that problem, whatever it is, be fixed soon?