I never thought about this but it is brilliant. You even have Alexius with you to oversee the attempt, and he's proof that it's possible (it's presumably how he managed to get to Redcliffe before you and change Fiona's timeline).
No, I mean you deal with Alexius, then go from Redcliffe to Therinfal. It's as if you went to Therinfal from the start since Redcliffe is on the way to Therinfal. Basically, IHW should just be a pit stop for the real quest in Therinfal.
You have no idea how much time passed in the various jumps it took to set up the meeting with Alexius.
You received the letter at Haven. Logically you would simply arrive at Redcliffe and see Alexius soon after. Five hours tops.
You go to Redcliffe, meet with Alexius, meet with Dorian, go BACK to Haven, meet with the War Council, plan the assault on Redcliffe, while you wait for Alexius to receive your agreement and reply, wait for your soldiers to get into position, and then go BACK to Redcliffe to meet with Alexius. That's not five hours.
I wasn't referring to all that. Just the part where you decide to go to Redcliffe Castle. That takes five hours at the most.
I suspect that after you send the message to Alexius telling him you agree to meet, he sends a message to the Venatori saying "Herald took the bait, start stage 2" and that's when the Red Templars take over Therinfall Redoubt--because *they know you're occupied*.
Impossible. You arrive at Therinfal and Denam confirms that your early arrival has foiled the plan. It had nothing to do with the Herald going to Redcliffe or not, Envy needed time to turn the templars red. It's all about if you get to Therinfal in time or not. Redcliffe wouldn't have delayed you that long.
Plus you had to arrange for a bunch of nobles to get together and bully the Templars into talking to you. That would have taken even more time, and once you dealt with Alexius the Venatori and Corypheus would know the cat was out of the bag--they wouldn't wait.
No, you can arrange for the nobles to go to Therinfal, and then you can go to Redcliffe. Then you should logically be able to leave Redcliffe after you're done and go to Therinfal.
As for Envy knowing, the fact that the Herald is at Therinfal at all is devastating to the plan. It doesn't matter if the Herald knows or not. The Herald was not supposed to be there. The plan to turn the templars red could not be rushed. It had a clearly set timetable. Redcliffe's timetable is much sooner, as you must solve the problem before the Ferelden monarch(s) show up to kick the mages out.
If you go directly to Therinfall the story is that you arrived only BARELY in time to save the lives of a FEW Templars.
Nothing indicated that the templars would not have lasted another five hours without you. And if the templars had been at risk, Envy would have initiated the attack before the Herald even arrived. They didn't attack because they couldn't. The only reason they attacked at all is because they were backed into a corner, and because Envy couldn't resist the chance to replace the Herald.
Better still why can't we go get the Templars to help us deal with the mages in Red Cliff, then have Corypheus and the Venatori, Red Templars that were not at Therenfall and, Calpernia's forces all attack haven together. The proceed as normal with both the mages and Templars united under the Inquisition. Makes more sense to want Templars to help fight magic/ a magister and, of course we aren't letting Tevinter have Red Cliff.
Because you only solve the problem with Alexius just mere minutes before Ferelden's monarch(s) arrive to kick them out. If you pass by Redcliffe to go to Therinfal, Alistair and/or Anora expel the mages. So we would only be able to do Redcliffe first, and then Therinfal.