How odd. I never even thought of importing a dead warden into Awakening but I'd just assumed you'd get the choices relating to other characters carry over and the Orlesian warden as PC. Retconning the warden back from the dead is a funny way to go about it.
The funny thing is that when you Google this, most of the results are from 5 years ago or so, when I guess a lot of people were assuming your Warden would end up being a character or even protagonist in the Dragon Age sequels. So players who made the Ultimate Sacrifice just got constantly berated by forum posters who were all, "You killed your warden. Now pay the price of none of your decisions mattering, since obviously, the US ending is essentially just a failure condition, like killing Shepard at the end of Mass Effect 2."
Five years later, that now seems absurd, but it does make me wonder if BioWare, itself, felt the same way at the time Awakening released. Hedging their bets in case they needed to use the Hero of Ferelden again in the sequel.
Honestly, it's kind of embarrassing in retrospect the way Dragon Age 2 made you basically disavow your chosen ending if you wanted all of your major decisions from the main Origins campaign and Awakening to carry over.