its fine for fractal, compare the following
Sage = 23 x 8 HP per turn
6 Feral Bond = 23 x 6 HP per turn.
its not much more powerful even with full field and full hand, only 46 HP per turn, and at these points... its negligible.
Well, now compare it to photon.
Maximum Effect:
36
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+ 93
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= 4 Fractals + 23 Sage + 6 Feral Bonds + 7 cards in hand = 299 HP per turn
36
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+ 24
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= 4 Fractals + 23 Photons + 6 Feral Bonds = 138 HP per turn
Conclusion: When cards-per-combo is held constant, cost-effectiveness in terms of quanta (129 for Sage and 60 for Photon) vs. HP gained (299 for Sage and 138 for Photon) seems balanced when the effect is maximized.
Maximum Practical Effect (100 HP):
27
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+ 33
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= 3 Fractals + 11 Sage + 3 Feral Bonds + 6 cards in hand = 99 HP per turn
36
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+ 20
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= 4 Fractals + 20 Photons + 5 Feral Bonds = 100 Hp per turn
Conclusion: When the HP gained is held constant, the cost-effectiveness in terms of quanta (60 for Sage and 56 for Photon) and cards-per-combo (7 for Sage and 10 for Photon) seems to lean towards Sage being more powerful than Photon. For this reason, Sage may need an increase in cost.
Also, as shown in your calculations, the Sage version is more consistent and less vulnerable to PC because you heal more given you don't have Feral Bonds in the Sage version.
For these reasons, I reckon I should change the card to 4
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(0 | 4) and 3
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(0 | 4). This will make it (the unupgraded version) more durable while having the same cost as Sanctuary and requiring 50% of your hand to be unused to heal the same amount as Sanctuary.
Thoughts?