I don't pretend that these are anything more than my own opinions. And I certainly don't think anybody should or does care.

The more you talk about the possibilities of why Ishy fought Rand in the sky, the less sense any of it makes. If Ishy really wants to kill or capture Rand, then why the hell is he dueling with him in the sky? If it takes all his effort to maintain such an atmoshphere, why bother doing it at all when it makes it much more likely that he will lose? If his channeling won't work because somebody has sounded the horn, then why did he opt to fight there in the only circumstances in which he would have a realistic chance of losing? If TAR effects are better than channeling in TAR, then why not use those? Willpower and belief only matter in TAR if you understand that they matter, which Rand didn't. Rand couldn't have even understood he was in TAR (if he was in fact there, partially or entirely). Rand perhaps would have been utterly helpless in a TAR battle at that point.

I may need to reread the scene, but the way I remember it Ishy really didn't want Rand to stick that sword in him. The best way to avoid that would be to not fight him in circumstances that force him to forfeit all of his best advantages.

Are there other possibilities? Of course there are. It is a make believe world so the possibilities are endless. It could have been a quantum flux quake that forced Ishy to fight Rand in that fashion. It could be any number of things. But none of it makes much sense, so I don't feel bad about saying that it feels like that scene isn't totally coherent with the rest of the series.

And the Lanfear scene is still ridiculous IMO. She is full of the power, in an absolute rage, using an angreal, she has just brutally murdered Kadere but has the wherewithall to gently do no real harm to Lan when it would have taken no more thought or power on her part to blast him to hell or use enough force with a club of air to crush his head or break all of his bones. It is nonsense. It probably would have taken less effort for her to kill him than to avoid killing him in those circumstances. Certain characters needed to be alive for events later in the series, so some scenes wind up being a little akward, like this one. When I read that scene, the outcome of no good guys getting killed or seriously hurt feels clumsily forced. That is my main point. I love RJ, but he didn't nail it every single time. I'm willing to accept that.