The major problem with any Russia retaliation will be Turkey citizens.. it could raise the popularity of Erdogan the pig..and thats the last thing Putin needs. It could encourage hundred of thousands of "volunteers" from Turkey to join and invade Syria.. So im sure the Russia government had to study plans in case planes are shot down. by Turkey or Israel..
Public opinion will be really important in everything Russia does.. if Europe backup Russia
and Condemn ERdogan , then Russia will be in an easy position to retaliate Turkey without
US managing to Isolate Russia..
What is more important for Russia is to get Europe support and to not allow its operation to be interrupted by Turkey or US provocations.. how they will do that? is the question..but with full support of Europe Russia will easily retaliate and turkey will get sanctions by Europe. we will see.