I have the older D version of the 85/2.8, and it's certainly a very nice lens, and grand fun to have, but it's not likely the lens to rach for for landscapes unless one is doing a panorama. For this, the newer style shift lenses (which go both left and right without rotating) are quite nice. The old 35 mm. PC must be flipped to shift to both sides, making it a little harder to keep steady. On a tripod, it's quite easy to do a three shot panorama, giving the effect of an 85 in height and about 40 in width. If you can shift the tripod mount a little, you can extend it a little more without inducing a lot of distortion. If there's nothing near, parallax is no issue, and the shot looks nice and straight.
But I rather doubt the 85 would work well for the kind of near/far depth of field you are speaking of. It's fine for scenes with little or no foreground. I've never tried focus stacking, so I don't know how it would work for that, but if you're doing that kind of shot i don't suppose the tilt and shift would make much difference. As for whether it's worth the price, who can say? I got mine used for less than half the price of a new one, and probably still don't use it as much as that cost warrants, but I'd hate to lose it. It's a beautiful piece of work, but also rather difficult to use well. I must confess that part of my reason for wanting it at all was the "gee whiz" factor. I use the 35 mm. shift lens much more often with a DX camera, where the ability to shift adds some useful features to a normal perspective, cutting the photographer and his shadow out of low light shots, mirrors and windows.
Here's a long ago experiment in stitching with the 85 (resolution of course awful because I reduced it to a total of 700 pixels for the old photo.net forum). This is a five shot stitch, using the lens shift for the center three and a sliding tripod mount for the outer two, and in its original form it was pretty sharp. I liked the effect, but cannot say I do it very often.
