Some initial observations on the Russian Army Battalion Tactical Group (BTG) concept as implemented in Ukraine:

(1) BTGs are simply battalion-sized, task organized combined arms teams. All major armies have done this since WWII.

(2) The Russian Army's current emphasis on BTGs (vice regiments/brigades) is due to a lack of available manpower - they were used an as expedient during the Chechen war that the Ministry of Defense adopted wholesale in 2013 as a manpower hedge.

(3) Russian Army BTGs and doctrine are built around firepower and mobility, at the expense of manpower.

(4) Western analysts believed that Russian BTGs were capable of networking long-range fires in real time (or near real time) i.e. the 2014 Zelenopillya strike. http://www.dupuyinstitute.org/blog/2017/03/29/the-russian-artillery-strike-that-spooked-the-u-s-army/

(5) It turns out the BTGs can't actually do this. They cannot even communicate via secure means, much less target and strike quickly and effectively at long range. This negates much of their supposed combat power advantage.

(6) The Russian BTGs appear unable to execute competent combined arms tactics. This is a fundamental failure as combined arms have been the sine qua non of modern fire and movement tactics since WWI.

(7) This shows up big in the lack of effective infantry support. BTG infantry cannot prevent Ukrainian mechanized and light infantry anti-tank hunter/killer teams from attriting their AFV, IFV, and SP artillery. This is the primary job of infantry in tank units.

(8) It is not clear if this is due to ineffective infantry forces or insufficient numbers of them in the BTGs; probably both are true.

(9) The net result is that the BTGs lack the mass (i.e. infantry) necessary to take defended urban terrain by assault. At least, not at a reasonable cost in combat losses.

(10) The leanness of the BTG manning (~ 1,000 troops) means that they cannot sustain much attrition without suffering a marked decline in combat power and effectiveness.

(11) It will take a thorough analysis to determine if the performance of the BTGs is due to inherent flaws in Russian Army personnel and training or flaws in their doctrinal approach. Again, both are probably culpable.

(12) In any case, these problems are not likely to be remedied in the short term. Fixing them will take a major reform effort.