I played a warforged in a campaign for a while, the DM said my wildforms had to still look like a warforged. I think it should be able to go either way though, magic and all. I just bought into it and RP'd it as best I could though.
Personally, given beasts don't have a high AC, I don't think it's game breaking if a transformed warforged keeps the integrated armour, at least for large beasts (brown bear, elk, etc) but for smaller, more nimble beasts, taking a long rest to "remove" the armour would be necessary.
Wanna be a bird? Good luck flying with all those armour plates weighing you down.
Wanna be a sneaky panther? Buddy, you weigh more than your barbarian like that.
So yeah, we're incorporating a need to think ahead at the long rest, ultimately it's leading to not having the armour most of the time, so when he does become a bear, he's not often one with a high AC. We find it's a good compromise, letting the druid have his cake and eat it, but he has to think about it first.
here's the problem with Warforged. The eating, breathing, sleeping thing. May or may not change. It doesn't actually make a huge difference much of the time. These abilities don't affect most game play and an agreement can be reached on the rare time they might be affected by that party. It's a nice bit of flavor that doesn't exactly matter much in most of the likely scenario's.
The problem is more in their resistances and in their integrated armor. As these two abilities are written are directly described as being physiological makeup to the war forged and ingrained deeply in the makeup of their bodies. Integrated armor talks about how it's basically having control over the makeup of your body and it requires a rest to reset that and use it differently. And the resistances are from the inherent non-fleshy nature of them materials of your body. On top of this they have an inherent effect on a lot of gameplay for Druids.
Some DM's may rule somewhere in between because it can be essentially a cool effect. But if we look at these abilities as written and the impact they have on play. They problematically collide and these abilities based on what we've seen of other races (such as the Tortle and their shells) then when wild shaped these abilities disappear because the make up of the bodies they turn into are not capable of them just like the Tortle is not capable of using it's shell for innate protection and most races are incapable of using dark vision without changing into a creature that has it.
As for the Lore Argument. That is a very messy argument. And the Curse isn't exactly confirmed. That's just the excuse that is given for why the Drow were driven underground in some editions. 1st edition as somebody pointed out was particularly harsh and just about everything that was evil past a certain degree suffered certain penalties for it. Second edition let go of some of that but introduced a fair bit of lore that some was known as fact and some wasn't (For example not even the elves actually remember what really caused the rift or drove the Drow underground and they only have stories because it happened that very far in the past). And the Editions have kind of waffled a bit between the two ever since.