You can't really do miniatures with the 17mm anyway, too slow, too wide. I see one in that review, but even for miniatures, it's lame.
No filters unless you rig up something is definitely it's downside. It does take x1.4 extenders fairly well (IQ still way better than the 17-40 or 16-35)
Fed up with tilting buildings and trees? Freaking tilting trees was the #1 reason I got this lens. Landscapes with tilting trees just don't work for me.
Heavy? Not sure how heavy the 16-35 is, but the TS-E 17mm is no heavier than the 24-105. In fact I would say I was pleasantly surprised how small and not-heavy (I won't use 'light') it is. I don't think twice about putting into my bag (same cannot be said for either my 70-200 f4IS or sigma 85mm 1.4). Of course the 17-40 is smaller and lighter. From the photos though I was expecting it to be bigger and heavier than it is. The front element isn't really even that big really. I think somehow those photos of it make it look like a monster (especially knowing the size of the body it is usually seen with).
Maybe I just had it in my mind that it was big when it really isn't that bad, definitely worth the weight when hiking IMO.
(EDIT: well allegedly it is heavier than all those lenses, but maybe becasue it's so good, I don't know, but it doesn't feel that heavy. I'm honestly surprised, although I've never weighed my lenses, so it could well be true.)
Anyway, I think (up/down) shift is the most useful feature, followed closely by sharpness and then tilt for some landscapes. Still tilt can make the corners less than stellar at very close distances (thinking 2-3 ft here). Shifting for panos works and does give you a bit extra, but don't expect to get 180deg panos or anything close. Once you get used to the controls I find it a pleasure to work with (on a tripod).
Is it worth it? Only you can answer that. There are no real alternatives at this FL, you cant even get a medium format or some other MF 3rd party shift lens. I think it is still only $2100 at B&H for a week - you'll probably be able to sell it for that in 6 months when the price is back up to $2400+.
If you have the money and you really think you want this lens, then you HAVE to buy it. That's basically what I did.
Also think about how many of these are there used to buy (OK, one above, but not that many)? Ever hear someone on a forum complain about how they got a TS-E 17mm and didn't like it? Maybe becasue at that price you'd better be sure you want one, but if you do you're not going to be wanting to sell it I can assure you of that.
EDIT #2: one other thing I really like about shift - you get a 17mm (or close, probably more like 18mm) FOV with an image that doesn't look overly wide. Something about it IMO just doesn't look like a 17mm shot. Maybe the lack of distortion in the corners also helps there.