It's 's worth recapping for the umpteenth time how the war started: peaceful protests ruthlessly suppressed by the ruling dynasty.
Followed, inevitably, by an armed insurrection against the state. Further complicated by the emergence of the Islamic State.
All along, the west has tried to persuade Assad to back off, but UN efforts have consistently been blocked by Russia and China. As the conflict has intensified, many moderate Syrians have felt let down by the west, and the UN in general, and this disaffection has swelled the ranks of extremist groups.
As for Russian involvement, Russia has been involved all along, so it is hard to imagine how things would have progressed without them. Although it is likely that without it the war would now be over.
Certainly the last year of bombing has been a humanitarian disaster. And a lot of innocent lives would have not been wasted, a lot of people not as embittered by the perceived failure of the international community to help. A lot fewer refugees.
So from a "Better/worse" point of view it's a no-brainer