Incredible, there's the waterfall right on it. Woooshh, back in time you go, eh?
Heck epackage, that's a tough choice. Like you said, you might never see one again. You might always feel like your collection was 1 short of what it could have been - that's a bit dramatic maybe, but for a collection as significant as yours, hey, it's the oldest thing you have...!!!
I can see what you mean about the blue, but to me it doesn't necessarily take away from anything. We could easily convince ourselves that it is a sticky steamy midsummer evening at the falls depicted here, just after a heavy rain or storm, and the sun is trying to stab through the thick cloud, and the mist up from the churning water and the evaporation off the hot wet rock obscures our view - this was honestly my first impression, mostly owing to the blue glaze in the sky. And maybe there are fewer like this, with a dark sky like that, which might make it very unique.
I wonder what the chances of finding the lid and everything in one place are. Maybe holding onto this piece would give you a fighting chance at eventually getting all of them separately. And it's definitely a big, integral part. I mean, this thing holds the gravy!!! It's like you're half the way there.
If you bought it recently, I guess the longer you wait, the more reluctant the seller is going to be about giving you your money back. But, lid and base plate or not, just for now or whatever, just as a stand-alone piece, this thing is BEAUTIFUL.
Think long and hard about it and you'll be fine!