All right Gradius, since you had repeatedly asked about the Tal'darim matter in the other thread (http://sclegacy.com/forums/showthrea...We-All-Thought), I thought I'd make one here to try to explain things, and I'll try to tie as much of the lores together as I can, but I'm still going to use the SC2 lore to try to make sense of the SC1 lore.
When I wrote about the idea of very little progress had been made in the 3000 years after Amon was sent back into the Void, you had scoffed at the idea that Kerrigan's psionic energy alone did virtually all the work because there was no possible way she could be that powerful, even during her infested state. I agree with you on that. In this, I would like to refer to what TheBentOne had said on the battlenet forums: Kerrigan's psionic energy alone didn't revive Amon, it was merely the last thing Duran needed to push the proverbial boulder down the hill.
Recall the prison that Amon was put into when he was forced back into the Void. Now yes, there wasn't much progress made from 2439 to 2499 as the Zerg headed to the Korpulu Sector, since the Overmind didn't know the exact location of Aiur. It was vital that Duran gathered the psionic energies necessary in order to free his master, or the void prison he was stuck in would kill him. By the time of 2499, the situation had grown critical. Clearly Amon didn't have too much longer left to live, and Duran was getting very desperate.
You had asked why the hell Duran didn't just use the Tal'darim as a psionic energy source. The theory I have for that is simple:
Think of recharging a battery. The closer it reaches the 0% mark, the longer it's going to take to recharge. Or think of a man on the brink of being starved to death. The closer he is to that brink, the more food he's going to need to make himself full.
When Amon was banished into the Void around 500 BC, Duran's plan never once changed from simply gathering enough psionic energy to send to his master in order to free him from the void prison. But the more Amon is weakened in that prison, the more psionic energy it's going to need in order to free him. Likely by the time of 2499, Amon was already weakened to near death from being in that void prison, despite having drained Ouros's essence for the last 3000 years in order to keep himself alive. If that's true, it means it would require a huge amount of psionic energy in order to release him, and ensure he'd be relatively strong after he's released from the Void.
Now, you may want to look at the Tal'darim population: if you had looked at Slayn, you would've noticed the total population is only about 12 million. This is extremely small even compared to the Nerazim population Shakuras, which by 2506 was 194 million.
Furthermore, the Dark Templar were kicked off Aiur about 3000 years ago, whereas the Tal'darim left Aiur millions of years ago. We already know from Shadow Hunters that there weren't that many Nerazim when they were sent off Aiur via the Xel'Naga freighter ship (I don't know the numbers, maybe a few hundred or something, you can correct me if I'm wrong about that part). This could imply that the Tal'darim were even fewer in number when they left Aiur back then. After all, we were never given the numbers as to just how many Tal'darim Amon took off Aiur...
Therefore, it's entirely possible that even if the whole of the Tal'darim population on Slayn was sacrificed and their psionic energies transferred to Amon, Duran still wouldn't have had enough in order to help his master escape the void prison and restore him to adequate strength level.
This is when (relative to him) the miracle happened. Remember, however late in the day it was, the swarm's invasion of Aiur ultimately did occur. Amon had been badly weakened and almost to the point of death after being stuck in the void prison for so long, but with the Aiur invasion, it's possible Duran felt confident that this would finally bring him what he needed to help his master.
Unfortunately (this is how I see a possible theory would go), because Amon was so badly weakened, he needed way more psionic energy than Duran had originally thought. Thus despite the fact that billions of Khalai Protoss were killed on Aiur by the Zerg, the psionic energies collected still fell just short of expectations. For example, it could like by the end of the Protoss campaign in SC1, Duran had gathered about 95% of the total psionic energy he needed to help Amon.
To make things even worse, it was at this point in time that Tassadar killed the Overmind. The Zerg broods on Aiur laid scattered and broken, and despite the fact that their rampage continued (as Zeratul was telling Aldaris at the beginning of BW Protoss mission 1), this gave the Khalai people the chance necessary to escape to Shakuras. As a result of this, Duran's plans got thrown into disarray once again because the source of psionic energy he needed for Amon got cut off.
This brings us to Brood War, and Duran's actions there. The way I see it, in the beginning Duran sided with the UED because he was hoping that once the UED won, he could use their tech to produce the hybrids to keep things going with Amon's plan. After all, the forces sent the Koprulu Sector was just an expedition force, and that defeated the Dominion military just fine, so obviously the UED was a force to be reckoned with. However, Duran quickly realized that just making the hybrids would be of little use if Amon remained imprisoned in the Void. It's also possible that Duran didn't see the possibility that the UED could actually control the 2nd Overmind like that, though this seems unlikely.
A possible theory could be that when the UED declared to take over the sector, it didn't have to mean brute force to everyone. After all, in the 4th Protoss BW mission, when Stukov made contact with Artanis's fleet, he didn't immediately open fire on them, but rather demanded Artanis's forces power down their weapons. It's entirely possible that perhaps while the UED's plan for the Zerg involved brute force and subjugation, their plans against the Protoss might be to try a non-hostile approach first or something.
We'll never really know for sure, but if that was indeed the UED's plan, then Duran would have realized that there would be no conflict with the Protoss, and therefore would lead to no more psionic energies to be gathered to help Amon. Therefore, although he would lose a great advantage in the hopes of utilizing UED technology in order to create the hybrids, it was a sacrifice he had to make, since freeing Amon from the void should be top priority.
This now explains his actions in helping Kerrigan before the UED campaign in BW even ended, as Duran knew all along Kerrigan would betray her allies, and knew that Artanis would likely come for revenge for such actions (as indeed happened in "Omega.")
The problem, however was that unlike what happened in the Aiur invasion, the bloodshed here with the Protoss was much lower. Therefore, what I see possible is that by the end of the BW, Duran had managed to gather about 99.9999% of the psionic energies needed to free Amon and restore his strength. However because Kerrigan withdrew the swarm and went quiet for the next few years, Duran was denied the last "piece of the puzzle."
Now, you're probably asking, "Then why the hell in the immediate aftermath of the BW didn't Duran just use the Tal'darim on Slayn?" Very good question. I would have done just that if I was in Duran's position. Retcons and Blizzard stupidity aside, a possible reason could be because Duran didn't want the secret leaked out, and didn't want the Tal'darim to turn on him, since at that point in time he didn't have control over the swarm.
This brings us to the events right before WoL: likely by that point in time, Duran realized that it was ok to proceed with the hybrid production via Dominion and Moebius tech even though Amon was still stuck in the Void. In that regard, it would mean he had suspected all along that Raynor would succeed in the Char invasion in order to deinfest Kerrigan. Of course, this would be contradictory to the way he was acting in SC2, especially in the LotV epilogue where he had said, "You cannot resist forever, Raynor. You do not deserve to stand among gods."
In that respect I think Duran suffered the same problem Kerrigan did in her view about Raynor during the infestation years. Both of them seemed to share the view that Raynor was weak and feeble when going up against their personal forces, but was exceptionally skilled and could prevail regardless of the odds when fighting someone else's forces.