First paragraph: I agree, that irked me too. Especially for a biotic who can literally pull someone to you or stasis them. No way that should have happened. But the answer is obvious, isn't it? DLC isn't allowed to change anything
They couldn't survive, because that would alter the main plot (in potentially awesome ways).
For the second: Yeah... that's the main reason I have mixed feelings about Citadel (but not the only one). And why I headcanon and play it after a Breath Scene Destroy ending, and filter out the ongoing war comments.
In conclusion I thought Citadel added more to ME3 than it took away, and really want an even better version for Inquisition!
Hey, that's what I've elected to do as well! Of course, that headcanon comes complete with pretending the clone survives and joins the good guys. I like to think he has the "misfortune" of partnering up with Conrad Verner.
One of the things I like best about MEA taking place in the distant future and in another galaxy is that it gives us full liberty of the nonsensical endings. I am taking full advantage of it, and my happy ending to the trilogy makes me happy. Never thought I wouldn't be too bothered by my choices ultimately not mattering, but I think I don't mind because a soft reboot means that Bioware's poor choices also didn't matter.
Anyway, if the Inquisitor is finally given an interesting array of personality options, and if the content won't be jarring and empty simply because I no longer recruit IB, Viv, and Sera, then I'd be happy with a Citadel-like DLC for DAI. Maybe then our companions will finally feel like friends and lovers with chemistry instead of awkward coworkers.
OP specifically mentioned our DA2 companions, and considering everything in DAI, we can safely assume it's not gonna happen for DA2 companions and Hawke, specifically. However, I do think it'd be the ideal DA installment for it, so far, just from our strong and dynamic companion relationships and antics alone! Provided they wouldn't pull a "date rape is funny when a woman does it!" (a la FemShep and James) and have Isabela sleep with Hawke without their consent in this scenario. But they learned their lesson. Or, I hope they did, wtf.