Wall of text welcome, covered off most of my questions nicely!
I actually have no TV right now, I moved to Denmark 7 months ago and TV was low on the list for 'things needed in a new apartment', but winter is on the way and some distraction for the cold evenings is required. I don't speak Danish (yet), so it's pretty much exclusively for movies, tv shows and perhaps xbox if I get round to buying one of those.
I'd like to wait, the inevitable price drops next year would be nice. I originally planned to wait until January and see what the sales are like here, but 4-6 months when it's 0-5c from 6pm onwards isn't going to work with a 13" mbp as my only screen for entertainment.
My main issue is that, as you say, why spend so much on a TV now and settle for non-4K just because the content is lacking at the moment. £100-200 isn't really that much when you're talking about £500-1500 overall cost, in my opinion.
As an alternative to going full whack on a JS9000/JS8500 (DKK 16000 here, which is about £1600), there's the Samsung 55" JU7005XXE for £900 from my previous post or I found the Samsung 50" JU6875 (I think it's JU6800 in the UK) for £700. Guess I need to figure out what my cost/nice tv threshold is.