One more thing that failed was their BTG. They formed small and agile formations on the basis of combined arm warfare which (on paper) would be formidable on penetrating enemy line.
However reality has shown that Russians have messed the up too. They made this change but then they realised that they didn't enough money to equip them properly. From what I remember its maximum 10-14 BTG that were properly equipped. The vast majority of the others, were just downscaled versions of their older formations without any modern capability boost.
Lesson:
If you are going to do a military formation change predicated on them having new equipment/capabilities, you better be damn sure that you actually buy the equipment needed for that to happe.
They did not have enough personnel for their Kiev Offensive. They rushed to Kiev too quickly. They moved at speeds beyond which their logistics and supplies could cope with. All these blunders are plainly due to the assumption that the Ukrainians might give up as soon as the they showed up at the gates of Kiev. Otherwise, why advance so quickly. The rush to Kiev was done at speeds even quicker on a mile per time basis than the American rush to Baghdad during the Iraq War.
The Russians made the gamble that the Ukrainians might give up quickly and negotiate as soon as the Russians made it to the gates of Kiev. Otherwise, they wouldn't have rushed. I always make references to the 2nd Chechen War because that is a war that Russia fought in which it utilized a very cautious and patient approach and eventually succeeded, because it had learned of the costliness and humiliation of rushing things, undertaking very little defensive precautions and thereby suffering heavy losses, and as such they had utmost respect for the Chechens in the 2nd war.
I think there are many people who have the habit in life in operating under the principle of not respecting others unless they have shown that they are worthy of respect after having taken quite a few licks from such a person, even after having been taught a lesson by others before that should make them very cautious and stop assuming such an attitude.
With regards to both Chechnya and Ukraine, the Russians have been taught this lesson. If the Russians had been cautious from the onset, they would not be withdrawing from the Kiev front, even though they would not have approached as quickly towards the Kiev as they did.