I wouldn't count your chickens before they hatch.
The Russian withdrawal is far from total, there is and will remain a sizeable Russian complement in Syria, and any Turkish or Saudi military adventurism in Syria still runs the risk of bring them into direct combat with the Russians.
The Russian drawdown is certainly unexpected. But it doesn't actually change the dynamics in the region much, except maybe in Russia's favour.
Russia was never in a position to mount an effective direct counter against a determined Turkish/Saudi campaign in Syria given the geographic realities involved.
In fact, the drawdown almost feels like a bait for the Turkish and Saudi military.
The peace process is in place, the Russians are taking their newest and most capable toys home, but leaving enough forces in theatre to act as a tripwire where any Turkist/Saudi military adventurism inside Syria would almost certainly force them to attack Russian forces directly.
So, if Turkey or Saudi Arabia goes into Syria now, they will be seen as the clear aggressors who destroyed the nescant peace process and attacked Russian forces without provocation or justification. At a time when the west, especially key European NATO members, are up to their eyeballs with Syrian refugees and would be none too pleased to face the prospect of an escalating conflict and more refugees just as it looks like things might be starting to ease up.
That will give Russia a near blank cheque to retaliate as they see fit.
Other than the token bait force left in place for Turkey and Saudia Arabia to attack to give Russia the perfect pretext to hit back, Turkish and Saudi military options against Russian targets are extremely limited, whereas the far superior Russian long range strike capabilities gives them plenty of reach to hit targets deep in Turkish and Saudi territory with NATO almost certain to leave Turkey flapping in the breeze in such a scenario, since the already unsympathetic western public opinion towards Turkey and SA would positively turn toxic and hostile in the event of such naked and unprovoked aggression.
And the Russians are almost certain to hit more than military targets, especially in the case of SA. Cruise missiles + oil wells/refineries = Russian oil and gas profits.
The Turks and Saudis would have to be delusional and/or stupid to go into Syria now.
