Whether you will have one or the other depends also a lot on the determination, preparedness and fire-power of the defenders. In Iraq majority was against Saddam and didn't really want to fight, while people in Ukraine cities seem to be very united and determined to defend every house, and also have been supplied with a lot of personal anti-armor weapons and had months to plan the defenses - so regardless of the Russian doctrine, I really doubt Russian army will be able to move fast this time... unfortunately, as you said, that means a lot more civilian casualties, and a lot more destruction...