First, there is more than one Thelemic system designed by Crowley. They still have Thelemic philosophy and adaptations, but come from different angles.
'Sacrifice' is still relevant in both systems; the GD version is R+C based and Christian, the Thelemic version is R+C based and .... Thelemic
The sacrificial aspect in Themela, as Crowley outlined it in some of his rituals seems more like Buddhism ; 'glorification' isnt achieved BY suffering, glorification comes after elimination of processes that 'holds one back'.
Again, if one is attached to the old, elimination can seem suffering, but if one is attached to the new , and realises the dynamic it isnt suffering at all. So I dont think 'suffering' is key, suffering is the outlook, the process is the key.
In one of his R+C rituals , symbolising part of the post-mortem experience, the suffering represents the 'uprising' and elimination ( or triumph over) aspects of the personality, unconscious, etc. that arise after the 'first death' and the first 'false (illusory ) glorification' . In Buddhism these must be transcended while in the post mortem state ( see The Tibetan Book of the Dead ).
One can then move on to the next stage or return as a Bodhisatva (or Rosicrucian) to assist others to attain that level (or devote oneself to good works in society - eg healing and medicine ). Hence, as Crowley stated, this is the 'general stopping place' as further progress requires great devotion and renunciation.
He outlined the process in his translation of Levi's 'Hymn of Honorius'
"O Lord, deliver me from hell's great fear and gloom!
Loose thou my spirit from the larvae of the tomb!
I seek them in their dread abodes without affright:
On them will I impose my will, the law of light.
I bid the night conceive the glittering hemisphere.
Arise, O sun, arise! O moon, shine white and clear!
I seek them in their dread abodes without affright:
On them will I impose my will, the law of light.
Their faces and their shapes are terrible and strange.
These devils by my might to angels I will change.
These nameless horrors I address without affright:
On them will I impose my will, the law of light.
These are the phantoms pale of mine astonied view,
Yet none but I their blasted beauty can renew;
For to the abyss of hell I plunge without affright:
On them will I impose my will, the law of light. "
One that cannot transcend the 'dread abodes' becomes stuck in 'suffering' being persecuted by the forces of one's own 'astonied view'.
So the dynamic is still present, but it is understood differently - the Thoth deck still has the Hanged Man card.
Another difference is the GD being Christian / Osirian is the view on rebirth associated with the belief of the Sun going under the earth and being reborn. In one of Crowley's ritual systems - the OTO - he addresses this; the beginning rituals are of the Osirian formula (as the enrgy is still current in the world and most of us have been influenced by the paradadigm, so it is important to understand it ), but he also states very clearly in the ritual at the end of this 'earth' cycle that moden science has shown this is not the case.
The earth rotates so that some of us are in its shadow side away from the sun, he invites one to meditate on the significance of this discovery and how it might change the formula.