I think Almalexia stole a bit more divinity than Vivec. Notice how Vivec didn't go crazy, and she did.
Didn't he?
He's a poet: he has one foot on the golden road by definition.
Not that even that would be necessary around here.
I believe it's that Almalexia is a lot happier than Vivec, and if Oblivion taught me anything it's that happy people have colossal souls.
Proweller
Was simply followin the above line of argument and trying to compare - not necessarily supportin it but rather suggestin that what can be applied to happy can also be applied to other emotional states = it does not quite add up. As for Dremora and scamps - did you play Battlespire? The Scamps were not bigger creatures, but were very unhappy with their lot and somewhat rebellious - just lacking in physical strength.
Now Dremora Lords have magical power - are their souls bigger than a Twighlights? Or maybe a Golden Saint's? So that lets out 'mere' magica use.
Also you can add in various mortal creatures too and it seems that overall stats may have some bearing - physical power being only part of that and compare them to any creature of Ovlivion. And that produces a far clearer division.
It all comes back to 'killability' - how tough and how dangerous = there aint nosuch thing as a free reward!
I feel a key question that was only touched on earlier is regarding the rutual/s with the Heart? That turned them from 'ordinary' mortals into demi-gods and therefore infinitely more dangerous. What you cannot say for sure is what size soul they had before they became demi-gods - but I would imagine far smaller! As they were nowhere near as powerful then.
I suspect that the power you can draw for the Heart is NOT ordinary magica! It does not look like magica. It does not act like magica. It is on a different order of things - though magica is a small constituent of it. So I reckon the dreamer Vekh drew far less power from the Heart because he was not so Warrior-like, nor as greedy. He just went along with the currents around him = more of his ambivalence. Almalexia knew what she wanted and had murdered her husband to get it and she went straight for it and grabbed all she could get. She later murdered Soth-Sil because he had scruples and was a phsyjic
I think she always was a powermad crazy. Nerevar was not one of the great Indorils at the start - he became acknowledged as a great general so she married him lest he threaten her pre-eminent position as leader of Indoril - and when he got in her way to further power - the power of a Goddess (with big breaths) she disposed of him. What she was? Was more dangerous than Vekh - she held more power and therefore looked and felt more everthing that she wanted to look and feel - so when she made nice to 'the people' they felt a great sense of relief = the big carnivore is purring - how beautiful and loving it is
Let us stroke and pet it and tell it we love it and it will not eat us ... so the reward for capturing her soul is greater.
But also danger = the true measure of a soul because if a creature is dangerous it is powerful.
This makes power both mechanic rule and in-game philosophy - a good match