This is absolutely ridiculous.
And note, I play on Xbox One. Just because something doesn't affect me personally, it's never stopped me from being appalled by it.
To release the game only on new platforms would have been fine. In fact, I'd have liked that, because it would have meant getting a game more like the one we saw in pre-alpha. Regardless, they released the game on all platforms. It is not reasonable to expect players to think that Bioware might suddenly, with no hints that this might happen, completely drop support for 2 out of 5 of these platforms.
Warning players before launch that they even might not be able to release all DLCs on all platforms would have been questionable, but it would have made what they're doing valid, even if it's in poor taste. But to just abruptly say it, most likely with a new DLC right around the corner is despicable.
If you release a game, there is an expectation that all content will be available for all platforms, unless you tell people beforehand. They absolutely did not tell anyone beforehand. If they did, the player simply has to take that risk. But when you don't even know you're taking a risk... I'm probably repeating myself, but this is so wrong that I just need to say something.
To release this statement in the tone that this is great news, is a whole new level of not-cool, and it's insulting.
"Hey guys! We wanted to tell you that you won't be getting any more DLC! But this is *good*, because you can buy a $400 system to continue your journey with this new save importer! (As long as it's not cross-company). Oh, and you'll need to buy the game again. And the deluxe edition upgrade if you had it."

This also raises new questions, such as:
Will oldgen still get patches? They better.
Does this apply to MP DLC? Because I don't see why that couldn't be released on oldgen.
Will future packs like Spoils of the Avvar (bad as it is) be available on oldgen? There is no reason why they shouldn't be.
I'll let Cullen show my reaction to this announcement.

And finally: If this is how they're going to do it, the next DLC had better be good. If it's not simply amazing is size and scope, I'll be even angrier.