This is my Encore Ironhide (with a Reprolabels Sunbow face sticker, because that's what I was like back then...) in as close to the same angle as I could approximate to the teaser image:
It looks to me (and anyone can feel free to copy the image and repost side-by-side with the teaser if that helps) as though the cab of the robot is more complete (no visible seams) and the drone/chair head is situated higher behind the windshield. If the part hanging off the back is the "battle sled", it looks like it uses the top of the van only (much like Earthrise Ironhide), rather than most of the back of the van and opening like a mini version of Optimus' trailer.
Now, I don't dislike the looks of this as a G1-ish Ironhide redux. Also, according to the Wiki, G1 Ironhide was not part of Takara's original retail lineup, so maybe that makes it "fair game" for a redesign more than we've seen so far in Missing Link? In fact, looking at the tiny struts that hold the arms (and trying carefully to transform him into robot mode for the first time in a few years), I'm not sure how much room there would be to retain the original design and not have an end result that's more fragile than the original. If what we think we're seeing is the actual robot mode, and it's more sturdy for it, then that may have been the best choice available for this piece.
If, on the other hand, the original robot form is retained, and the extra torso bits, head, and arms are built into the battle sled, then I'm guessing that the battle sled is going to be a shell of its former...shell? This makes me sad only because my original Ironhide broke almost immediately; i have almost no memories of playing with him beyond his arm breaking. On the other hand, the Battle Sled I remember playing with well after the rest of Ironhide was gone, with the missle shooter becoming the "head" of an unconventional robot, not unlike a Scutter.
I don't know, I definitely want to see a full reveal and learn exactly how this figure does what it does. It may be enough of an improvement that I want to buy it, or it may be too far from the original design to feel like a "proper" Missing Link. It may even be both. I'll be looking forward to seeing more.