Same players, same stage, same ideals and statements. At a minimum, it will turn into another Iraq, with bombings and reprisal attacks continuing on indefinitely (three more civilians were killed just yesterday in a bombing in Iraq, a full year after the last Americans left the country). You're going to have the Iranian funded Shia trying to maintain their influence, the majority Sunni trying to assert theirs, you're going to have jihadist fundamentalist terrorist groups trying to re-create Afghanistan (our own state department finally admitted that many of them are in fact terrorists), and you're going to have a huge fight between ALL of them and the Alawites and Christians, who are widely blamed for supporting the Assad regime during this rebellion.
The tragic thing is that it will probably restart the fighting in Lebanon along with it. There have already been a number of violent battles in and around Beirut as factions aligned with the various sides of the Syrian rebellion have started each other there as well. It's easy to forget that it's only been 7 years since the Syrian military was pulled out of Lebanon after 30 years of fighting and occupation. It's still a very unstable area, and all signs point to the conflict not reigniting itself in Lebanon, but sparking a similar confrontation in Syria. Remember, Damascus is 200 miles from Aleppo, but is only 50 miles from Beirut and 10 miles from the Lebanese border.
I get that some people believe that the Syrians will come together for the good of the country, but I just don't see it happening. This is going to get a LOT worse before it gets better.