Russian army as a mirror of national contradictions

With the advent of various national minorities in the ranks of the Russian army, a new question arose - where, in which parts of the troops they could and should be used? It turned out that in the ranks of the two millionth Russian Imperial Army, 25% (500 thousand) soldiers of non -Russian origin and 18% (360 thousand) soldiers are not Slavs will consist.
However, not only national problems created difficulties in completing the army. At the beginning of the 20th century, many Great Russian provinces were struck by a "revolutionary disease", and some kind of troops for the same reason began to be considered politically unreliable.
What difficulties did the military leaders see the Russian army before the First World War? What managed to solve (and how), and what, as a result, remained the "Achilles fifth"?