There were a couple glimpses of his 'Sith eyes' during TCW... Like when he was using FL to torture Savage, for example:
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...But it was a very rare occurrence.
I believe that Dooku did not have yellow Sith eyes at all times, because he tended to keep his dark sided emotions in check and was not fully consumed by them like the other Sith were.
I like to believe the change of color occurs in the eyes when one fully surrenders themselves to the Dark Side. Dooku was obviously a conflicted Force wielder.
__________________ RealistRacism: "Sheevites, much like the Banites, were meant to increase in power with each member. From Lightsnake to Gideon to Azronger, this was supposed to be the case. However, knowledge must've been lost in some kind of Gravid-like incident, as Az turned out to be a mid-tier debater with a sub-par track record, sh!itting all over Tempest's legacy. Sad."
Almost like the movies that spawned his character were as poorly conceived as the character was useless.
Or they knew that Christopher Lee was dignified, not a comical looking cartoon retard.
__________________ Recently Produced and Distributed Young but High-Ranking Political Figure of Royal Ancestry within the Modern American Town Affectionately Referred To as Bel-Air.
I thought it was part of Dark Side Degradation. Dooku probably kept it in check even while "sithing out" by using the force to keep his body from degrading.
Not entirely accurate. Obi-Wan makes a point about it in The Clone Wars show.
__________________ RealistRacism: "Sheevites, much like the Banites, were meant to increase in power with each member. From Lightsnake to Gideon to Azronger, this was supposed to be the case. However, knowledge must've been lost in some kind of Gravid-like incident, as Az turned out to be a mid-tier debater with a sub-par track record, sh!itting all over Tempest's legacy. Sad."
__________________ RealistRacism: "Sheevites, much like the Banites, were meant to increase in power with each member. From Lightsnake to Gideon to Azronger, this was supposed to be the case. However, knowledge must've been lost in some kind of Gravid-like incident, as Az turned out to be a mid-tier debater with a sub-par track record, sh!itting all over Tempest's legacy. Sad."
Further proof that Dooku didn't consider himself like the other sith (from Dark Disciple):
Dooku (to Vos) - "Or you could join me again. We will defeat Sidious"
Vos - "I won't be your apprentice!"
Dooku - "No no, a team, equals"
Vos - "Sith don't work that way"
Dooku - "Are you and I ordinary Sith?"
I think that compared to other sith he wasn't fully into the dark side