Now that the rebels have this 'accomplishment' under their belt (and you can bet Putin won't be taking credit no matter what is found out) Ukraine should go all Israel on em.
Make a notification for non combatants to get out of dodge and then mercilessly go after every hardware asset and stronghold the rebels have and any one willing to stand in the way - regardless of collateral anything.
The time is right. Right now.
The world doesn't want hardware in the hands of those that can't be trusted with it. Claiming the airspace (informally as it was) of well established international routes? Wrong fight to pick.
Putin is suddenly at his weakest today on intervention. He wants to be seen interfering with Ukraine preventing another MH17 for sake of world stability?
It could be argued Ukraine has as much obligation to police these guys as the Palestinians do about Hamas, so to avoid Russia punishing them they should do this.

Goose meet gander.
Perfect timing with the new sanctions as well all the influence they have.
Too bad 295 died, but they body count against the rebels.
Seize the moment Ukraine, you will never have a better chance.