Janky? How so? I really liked how they tightly controlled the time travel stuff so that it couldn't easily be used again. I liked how could only work with the breach in existence, and how it was restricted to the time since the breach opened. I liked how you went forward once and then back, and no other messing about. I didn't have any trouble understanding what was going on. I mean yeah, it's a bit weird how your companions would just be sitting in cells near you and not dead, but I can forgive that because game mechanics, and they were quite touching when you met them.
Oh, it's janky.
Problem One is the alternate Fiona, the one that shows up in Val Royeaux. It's implied that this Fiona only existed in a previous timeline, which was erased when Alexius showed up in Redcliffe and did his time magic. So why does this Fiona cease to exist, but her effects - and the Inquisition's memory of her - did not? Alexius' time-magic got him to Redcliffe two days after the destruction of the Conclave, per Clemence's comments; this would have happened before Fiona met the Herald in Val Royeaux (the Herald didn't even wake up from coming out of the Fade until
three or four days after the Conclave's destruction, depending on how you interpret Adan's notes). Alternate Fiona would have to have been unhappened, just like the Dark Future was unhappened when Dorian and the Herald returned to 9:41 Redcliffe.
A week or so ago, some people claimed that this was accounted for by making a sort of "time bubble" within which Redcliffe existed, fueled by the rift that you close in front of the town gates on your way to meet Fiona at the Gull and Lantern. Supposedly, alternate Fiona existed outside the time bubble and then disappeared after she returned to it, or something similarly poorly explained; this time bubble also apparently acted as a force field and kept everybody out which is why Fereldan troops show up immediately after Alexius' failed ploy with the amulet. This doesn't fly either. Inquisition forces had already reached Redcliffe by that point; a scout meets the Herald at the gates and he had already talked with Fiona and the mage leadership, long before the rift was sealed. And "creating a force field/time bubble" is
not how the amulet is demonstrated to work. It opens up portals, nothing more and nothing less. (Apart from that, it'd be impossible to feed the town if nobody could get into the gates, but since BioWare writing rarely takes food into account that's a bit of a wash.)
So we are left with the entire plot hinging on a Fiona that should not,
cannot exist. The only way I can think of to account for this problem is to blame it on Dorian's fears about time travel: that it is tearing apart the fabric of reality and destroying causation and creating random people where they shouldn't actually exist. But that is never actually demonstrated apart from this single instance, and it's really quite an unsatisfactory explanation for a slapped-up narrative. Why doesn't the demon army from the future show up when the Inquisition is marching to the temple to close the Breach in "In Your Heart Shall Burn"?
Problem Two is more of a minor thing: how Alexius apparently managed to defeat Leliana, two companions (possibly including an actual god and the Hero of Orlais), and a hall full of Inquisition soldiers...by himself. And imprison them all. When the Herald and Dorian are whisked away to the future, that doesn't change the fact that Alexius has got several arrows pointed directly at his throat, with no guys to help him. OKAY THEN. Look: it makes sense that without the Herald to close rifts and the Breach, and without foreknowledge of Corypheus' plans, that Corypheus would steamroll the world. The Dark Future's existence in and of itself is perfectly reasonable. What doesn't make sense is how Alexius survived to see it, and why the people in the castle were defeated and imprisoned
before Corypheus' victory. (And also: HOW DO THE VENATORI IN THE CASTLE GET FOOD IF DEMONS HAVE KILLED OFF ALL THE VILLAGERS. But that is a standard
BioWare fictional writing issue.)
Problem Three is a meta-problem, not merely for what time-travel is used for, but for what it is not used. For somebody whose time-travel should theoretically give him a great deal of power over the time period after the Breach, Alexius does not seem to be terribly well prepared for the Inquisition's arrival at Redcliffe. The Inquisition does not appear to be expected or welcome; although this interpretation mostly relies on comments from the town's mages, Alexius seems to have been surprised and his plans derailed by the Inquisition's arrival and forced to cobble together a transparent attempt at a trap in order to deal with the Herald. If the whole thing was a setup for the Herald, then he should have taken her in the Gull and Lantern (or, hell, at the gates of Redcliffe) instead of drawing out negotiations and offering the Herald every opportunity to escape the trap. And since Alexius could know when the Herald was coming - y'know, because he had the amulet and could go back to warn himself as soon as the Herald and her party left the Gull and Lantern - it's truly bizarre that he didn't.
And there's a good chance that the barrier to using the amulet isn't
that high, because Alexius uses it dozens of times in the Dark Future to try to reverse the events at the Conclave, and because there's nothing that seems to be all that tough about using the amulet in Redcliffe when he sends Dorian and the Herald into the future. Admittedly, this is guesswork and probability rather than an outright plot hole, but it's not that important.
What's worse is what happens if the Herald goes to Therinfal instead of Redcliffe. Or rather, what doesn't happen, namely: anything! Even if Alexius couldn't prevent the Herald from becoming, y'know, the Herald, he could still work to prevent the Herald from going to Therinfal. He could have warned the Red Templars. He could've warned
Corypheus. He could pull any number of countermeasures in the time between the events at Therinfal and the closure of the Breach which ends his time magic's usefulness for good. But he doesn't. He apparently sits in Redcliffe with his thumb up his butt until his time magic's usefulness is destroyed with the Breach's closure, at which point Corypheus executes him for his failure and replaces him with somebody competent.
Now, this last bit isn't fully a problem with time travel's use in the plot itself. It's not a plot hole (and I truly hate that term so I feel annoyed with myself at having used it, but there isn't a better one that I can think of) like Fiona is. You can explain it simply with Alexius' staggering incompetence. But I'd prefer not to do that, because enemies that are written up as staggeringly incompetent aren't very good enemies.
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Now, the things you mentioned are true. I like that time travel relied on the Breach, and was for lack of a better term time-bound to the Breach's existence. I like that it wasn't overused. But introducing time travel inherently causes a lot of problems for any narrative, and although the writers dealt with some of these potential issues they did not deal with all of them.
Therinfal's just a tighter story, IMO.
As to Leliana, it was horrible but she was amazing, and it stiffened my resolve to defeat Coryphytits.
I'll just leave
this here. (The associated conversation draws on a fair number of these points, fwiw.)