i get the smell of nids' too. Nids' are consumers of planets so it makes sense. Plus, the reason the developers didn't include nids' in the first DoW or any of the expansions was because they said they didn't think they could do justice to the nids'. From what I've seen so far, this new game engine and everything will be more than enough to do justice to the nids'
Plus, they've said they're going to be focusing even more on the battle aspect than before. This was seen as a problem for a nids' army cause they don't use power or requisition or develop technology the same way the other races do. It'll be interesting to see how they've tackled that.
Plus, come on! How many fans have been screaming for nids' to be included? No way they'd ignore em.
"There is a cancer eating at the Imperium. With each decade it advances deeper, leaving drained, dead worlds in its wake. This horror, this abomination, has though and purpose which functions on an unimaginable, galactic scale and all we can do is try to stop the swarms of bio-engineered monsters it unleashes upon us by instinct. We have given the horror a name to salve our fears; we call it the Tyranid race, but if it is aware of us at all, it must know us only as Prey."