I think that you have hit on a very good topic. I would spend some time focusing on how both political orders operate without a sense of limitation or institutional check. In Orwell's vision, this is its primary source of terror. Big Brother and the ruling order of Oceania understand individual thoughts, control them through technology and intelligence operations, and ensure that there can be nothing else other than allegiance to Big Brother. It is a realm where there is no secondary check of power, nothing to limit its growth and enhancement. In Miller's vision, this is a similar configuration, minus the technology. The accusations that Abigail starts sets in motion a political machine where there is no way to limit its cancerous growth. Silence and obedience are the only ways to live in this set up for those who speak out are immediately accused of being a witch themselves and condemned. In both political orders, obedience becomes the only natural consequence to consciousness where the political authority is unchecked and unrestrained.
Both texts, 1984 and The Crucible, cite a dystopia that places fear above freedom in order to divide society and punish heretics.
In the theocracy of Salem, there is no separation of church and state, so Rev. Parris can abuse his position to acquire land and settle land disputes. He uses fear of the devil as an unchallengeable means of attaining authority and punishing those who question him. He ferrets out those who deny his authority (Proctor) and exiles and punishes them for unrelated crimes.
Similarly, O'Brien (Big Brother) uses nationalism as religious fervor to control the masses. Like Parris, O'Brien is a double-agent: he appears to serve the rebellion, but he really serves the state. O'Brien uses torture in the Ministry of Love (a kind of anti-church) to carry out his dirty work.
In the end, both heroes are destroyed by the state, although Proctor retains some dignity and hope for the future.
A few from 1984:
The torture and abuse of anyone found to be in opposition to the Party. There are incredibly stories about O'Brien and others who were caught and tortured in the past, and we learn about some of the torture of Winston and Julia from their own descriptions of it.
The fact that Big Brother and the Party are very likely launching missiles at their own populace in order to keep them afraid and filled with hate for whichever enemy fits that day of the week.
The revision of history according to the Party and Big Brother, obviously something Winston was very involved in.