By far the most dangerous of the current conflicts is Ukraine as Russia is nuclear armed and has / is going through a major modernization program. Their latest submarines are much quieter and much more difficult to detect, hence the new US blimp based cruise missile detection system, where the new generation of medium sized Russian submarines can carry nuclear tipped cruise missiles. Putin and the Russian leadership are convinced they can win a nuclear exchange, due to the Moscow ABM system, full population trained and practiced civil defences and being a very large country with mostly low population densities outside of ABM defended Moscow and a few other key cities, making destroying all of Russia more difficult than the USA and Western Europe. All of the other conflicts with IS, Israel / Palestine, Syria and Ebola (proven vaccines and medicines can be made available quite quickly) are easily containable depending upon how ruthless the West wants to be.
What do I think will happen in Ukraine. I can see three possible scenarios: The least likely at present is Russia reaching a face saving agreement with Ukraine, where Ukraine agree not to join NATO or the EU, the Donbass becomes an independent federalized area that has final say (Putin say) on all Ukrainian major political decisions and recognition of Russia's annexation of Crimea. These terms would be a red rag to a bull to many military units in Ukraine that have spilled much blood over defending Ukraine, with their democracy being replaced by a right-wing military dictatorship if this was agreed. So from both sides it is unlikely and Russia has an additional difficulty where nobody believes what they say or that they will make the slightest effort to stick to any agreement. Russia may have to change its stance during 2015/16 where it is going need access to Western capital markets.
The most likely one in the short term, that may well run into the very long term, is a smouldering conflict, which may include Russia attempting to grab more territory a bit at a time to try and stay under the radar of any increase in sanctions and the US supplying defensive weapons. Each time Russia doesn't like something Ukraine is doing, they will turn up the heat in the Donbass conflict to show their disapproval. For this reason I can't see it becoming a frozen conflict. This will blight the lives of millions of people in East Ukraine with the Donbass stagnant as a semi-post conflict derelict mess, where Russia is trying to push the future rebuilding of the region into a Ukraine / Western problem and on the Ukrainian side of the border, heavy border fortifications and being on the receiving end of regular Grad and artillery attacks. At the moment both sides are hoping that economics are going to be a deciding factor. Ukraine is near to defaulting on its sovereign debts and has almost run out of foreign currency reserves and is going to need Western support, Putin is hoping this won't be forthcoming in sufficient quantities. The other side of the coin is Russia's economic problems where they are not far behind Ukraine and will probably default in the next 9 to 18 months if their economy does not improve with higher oil prices (unlikely), reduced Western sanctions (more likely if war kept low key enough) and no further major collapse of the ruble against the dollar (USD will carry on strengthening in 2015, against virtually all currencies on the back of cheap energy prices and a growing economy, and maybe Fed interest rate rises and I can only see the ruble going in one direction, south). By default this conflict would stop Ukraine joining NATO and probable the EU until dispute is resolved, achieving two of Putin's aims.
The third scenario is Russia going all in and starting a general war in Ukraine and annexing substantially more territory. The West's pathetic weak response so far means this can't be ruled out as Putin's calculation is that the West will do little again and Russia has the second strongest conventional forces after the US. This would involve annexing 50% or so of Ukrainian territory to create a new Putin owned country Novorossya. The third option will probably be the fastest route to Putin's demise as it will become another Russian Afghanistan.
STMO is correct, all we can do is guess and surmise as it will be Putin's call and he has probably not made his mind up yet. Putin tends to be quite impulsive (by accounts quick tempered bully, with some instant bad revenge style decisions) and think cunning short term tactics and advantage, rather than deep thought long term strategies, which is why things are going very badly for him and will get much worse long term. His blundering in East Ukraine means that the Ukrainian people now have a purpose, other than stopping Putin and that is planting the country firmly in the West with Russia isolated as much as possible. There is a citizen inspired boycott of Russian goods and services and Russia has stopped most Ukrainian exports to Russia, but Ukraine's exports to EU countries is growing rapidly as part of the realignment. The West's carrot (loans to keep them solvent) and stick (no loans and new Euromaiden) means that key people from abroad have been brought in as ministers to help modernise their totally corrupt bureaucracy and since independence there is a real reform mood from the Government, which will go under route and branch reform. They have brought in a Lustration law which virtually all civil servants and the judiciary will have to pass over the next two years to keep their jobs.