Although not fatally heretical, and certainly not so evil that those who hold to it cannot be considered Christians, Annihilationism has a lot in common with Universalism. At first, this link is hard to see. The former view still contends that Jesus is the one and only way to be saved, and that therefore, those who do not come to the Father through Him will not come to the Father at all. On the other hand, Universalism teaches that all will ultimately be saved in the end, though there are about a million different views on how.
The link between Annihilationism and Universalism, however, is in the extent of punishment. Annihilationism would have to contend, and indeed even does argue, that punishment should be proportional. It is unjust, Annihilationists claim, for God to levy an eternal punishment for a finite crime. Yet, they themselves must believe that the punishment is eternal; only the consciousness of the sinner perishes. But do they not perish forever?
Here's the problem, however: Annihilationism can only argue proportion if it also argues for a second resurrection. Tell me, what do we do with criminals once their "debt to society" is paid? We let them go. Steal a car, get a few years in prison, walk right back out and hopefully don't goof up again. You can turn your life around. Your punishment doesn't end with a final, permanent blow.
In the same way, if Annihilationism was true, sinners would suffer a temporary punishment, but after serving their time, they would have no further debt to pay. So why could they not be given a second chance? They did the crime, but they did the time, too. Therefore, unless you want to flat out admit that yes, an infinite punishment is proportional for a finite sin, you must suggest that God can simply release the sinner with a clean slate.
Of course, this is not quite Universalism. Releasing a sinner with a clean slate could as easily mean they served their time in Hell for sins committed in their previous life, so now they get reincarnated into another. If they sin there too, off they go back to Hell, just as a released convict can be convicted of new crimes. But it could just as easily mean they took the slow route to Heaven. Hell could basically just be Purgatory that Christ enabled believers to skip.
It is true that God believes in proportional punishment. In fact, this is yet another reason Annihilationism does not work, as it ultimately means all sin leads to the same non-existent road. A permanent death for both Hitler and Ghandi just doesn't seem fair. Even if they burn for different times at different temperatures, neither will know this. Indeed, this is precisely why God must resurrect the wicked to everlasting shame (Daniel 12:2). If death was a sufficient punishment, there would be no need for a second death. But the Bible does say those who "sleep" will be resurrected, some to everlasting life, some to everlasting shame and contempt. They are resurrected to everlasting shame and contempt.
In conclusion, therefore, there is a link between Annihilationism and Universalism. If sin is so finite that it can be dealt with by temporary punishment, then all men can, and indeed will, be saved. If sin is so severe that Universalism is impossible, then Annihilationism loses, if not its foundational claims, at least one of its strongest arguments. Annihilationism is therefore better than Universalism only in its confession of the severity of sin; so great that only Jesus can truly reconcile us to God by taking our sin upon Himself. Although not equal in severity, Annihilationism is still an error akin to Universalism, and should therefore be discarded.