Congrats on those great results.
People are generally a bit too hasty to say they've encountered a true plateau. They don't lose on a weekly basis and jump to conclusions.
Check this re: fake weight plateaus for example: http://leangains.blogspot.com/2009/07/questions-answers.html
So give it some time. You're a guy and should be losing pretty good on 1600-1800 kcal unless you're a real light weight.
I find that if I am in need of leaning out (or even plenty of times during "maintenance" periods, too) that shakes may not be a useful part of the equation, but that protein powder can be put to creative use making various "pudding-like concoctions.
I'll mix it with a bit of yogurt or perhaps some pumpkin, cinnamon, and nutmeg, or even coconut milk occasionally. Obviously the coconut milk can cause the calories add up if you get lax, but when I measure it out, I find that's no problem. And the thicker consistency when you throw together just enough of the right stuff always feels much more satiating than liquid.
Of course I freely concede that even this may not work out for a lot of folks and that, perhaps, I am an anomaly.
Likewise, I find nuts work for me during any type of phase, although I certainly agree that for someone who tends to get hungry easily, a legitimate serving size of nuts won't go very far. And the nut I'd put forth as bucking that tendency to skew the n-6:n-3 is the most calorically dense of the bunch, macadamia nuts. But I'm at a point where
I have control over this stuff, so I definitely don't disagree with the notion that nuts are not going to be any ally for many folks. Given that I already avoid using vegetable oils when cooking and such and that I eat wild salmon fairly regularly and supplement with fish oil when not consuming fish, I am not all that concerned about the n-6 content of nuts.
From a fat-loss standpoint, whether they stay in controlled amounts or go is likely neither here nor there, but I feel that there are a lot of beneficial things in there that aren't worth passing up simply because of any shift in the n-6:n-3 ratio of my diet. Of course this still goes back to context, as I would imagine that what I am doing are likely not staples of what those you directed this at are likely doing. Specifically, you made mention of the Western diet, so in that context, the potential downsides of nuts would certainly be magnified.
I should also add that I don't think of nuts as any sort of panacea for health, and fully realize that nutrients can be had via many sources.
But for now, I enjoy them, they don't hamper my results, and I'm able to derive whatever modest benefits are to be had from a health standpoint from eating them.
I suspect that even if you think I am "nuts" for still eating them (not that you would actually care about what I do or don't do, hah, hah), that enjoyment and results ultimately fall right in line with at least part of the general message you're all about.