@Quakingstar. There is literally no doubt about that, Itachi could have used Susanoo whenever he wanted to. If he felt the need to use Susanoo at the start of the battle with a killing intent, then he'll obviously kill him. But remember, Obito was purely trying to make Itachi as great as ever for Sasuke, so to easily manipulate him.
But Bro are you sure your latest post should be at this thread? and not the present Itachi vs Madara debate?
@Thekillman. Well Zetsu already showed us how the outveiw of the genjutsu battle was, both of them just staring at each other. It was Sasuke getting through this genjutsu that lead them to a shuriken battle(if that wasn't genjutsu) And him then using Tsukuyomi. It was like that battle, it was only shown that the genjutsu was taking time, but in actuality Sasuke was able to look through the genjutsus.
Well from Zetsu's comfirmation, he was going to use Amaterasu inside the building itself. But Sasuke quickly used a fuma shuriken(so fast that Zetsu exclaimed "so fast" lol) so to distract Itachi from doing the attack, and Itachi was already under the side effects of Tsukuyomi. and he was brought to the roof by a combination of a fire ball and a chidori.
Yes he did win the fight, with his susanoo. But remember he couldn't deactivate his susanoo because there was something he needed to do, like extract Oro and then he had to keep the susanoo intact with him till he walks to Sasuke in order to protect him from any more explosives or kunais his brother would have thrown at his brother who is openly walking slowly towards him. But yes, if Itachi wanted him dead then he could straight away do that with his susanoo.
Well taking Itachi was traumatized for life by that war and became a Pacifist, he might have used the Tsukuyomi in intention to make Sasuke like him albiet Sasuke's had a much bigger connection to the dead ones rather than Itachi seeing strangers die. This possibly was the first mistake of Itachi.
The thing is, unless Itachi was told by the frog sage or Hagoromo that Naruto was going to be Sasuke's best friend in the next 5 years, I don't why he would say that.
Sasuke could have had any friend, he could have killed any random boy or girl that he felt attached to.
It's in my mind that he wanted to test if his brother was actually worth sparing/saving and Sasuke passed the test, since Sasuke showed Itachi that he wouldn't need such a villainous way to be stronger, thus reliefing Itachi that his brother was worth saving after all. And remember Itachi regretted everything he did for sure. Since he understood that if he just believed in Sasuke, and told him the truth, he could have possibly changed their dad and the Clan's veiws. These are all Itachi's words, showing clearly that he wished things just happened differently and thus saw the mistake in his actions.
Though as a side note, it's interesting to see that as Itachi kept to his words, said that people only show their true selves when they are dying, and so a dead Itachi showed how much he truely felt and all.
Well I think the purpose of this thread had been done, and that is, give proof of Itachi not watering down his Tsukuyomi with reasons. And I think that most have already accepted that and I'm satisfied with it.
To the people who disagree with me. Well I don't think I have any other way to prove it anymore, it's been good debating with you all and I'm glad that this didn't become some serious discussion. Let's just go with our own opinions for now. So unless you have anything to bring up, let's call this discussion at a end, shall we? :)