I know Doug Tennapel (the main creator of EWJ) is working on the project, which is completely awesome, but since I first heard this news months and months ago, I've heard nothing about other members of the original EWJ development team working on the new installment. That'd be nice if some of the old developers could put their original thought into it. If not, then I'm still very confident in any team willing to put together a new Earthworm Jim (if you really play it with an open mind, EWJ 3D really isn't the worst game ever made).
Earthworm Jim is still my favorite game. I hope that EWJ 4 will be as memorable and absurd as EWJ 1 was.