I sort of got sucked into this thread late....
....I'm expecting the new Defender to be a unibody, EAS, scrunched-LR3/4 looking Rover with pretty good capability. Some will say not having the frame is a negative, and I'd agree...but that doesn't mean it won't be capable. Some won't like EAS but I think the air suspension of the LR3 and later models has proven more robust than people expected. The Defender will be pretty good if it proves itself early, and is available in all kinds of variants like high-utility-low-cost as well as "premium" models that might have more bling and cost more but not necessarily add anything off-road. I'd want to be able to remove the top, too...even though I live in WA state.
Oh...and on that LR4. If you want to wheel it, don't get one without the HD Package. 4-Lo not only does what others on this thread have described, but it simply gives you tons of torque at really low RPMs/speeds. It allows you to inch over obstacles with control and not having to rev the heck out of the engine. That's less breakage and more control.
If you are a mountain biker, think of riding over a trail and how much that granny gear helps you, whether you're climbing a hill or going over technical terrain. That trick of using S1 and HDC might help you go down a mild hill descent and give you some added control in non-technical off-road situations, but it's simply no substitute for 4-Lo.