I must admit that's a very intelligent (and costly) approach SwiftC. I admire the dedication.
I'm a bit more childish. I only care about "elite" characters, and most of the time they have to be Force-sensitive. That's why I will never ever own a Stormtrooper-related piece for example. A random soldier who can't aim? No thanks. I know they are incredibly iconic, way more than most Jedi or Sith, but I just can't bring myself to care enough to spend the money.
Now a Death Trooper PF? Maybe, we'll see if they really are that good in Rogue One. Love the look, that's for sure.
Personally, even if I loved the introduction to Rey on Jakku, I would much rather have a PF with the clothes she's wearing when she meets Luke, or whatever she'll be wearing in VIII (probably the same thing). I want a strong representation of the character rather than one where she didn't understand her powers yet or was barely learning to use them. I know, that's weird.
Also, let's see if Luke makes her build a new lightsaber or not. The one she has for now isn't really hers and a proper Jedi knows how to build one. It would be nice to see the subject truly covered in a movie, it's barely touched upon in that deleted scene from ROTJ, that's it...
I only focus on high end pieces (mostly PF's and high end replicas) so that's a constraint, can't get everything when each one costs at the very least $400 nowadays.
Pretty sure I will get Kylo but I am waiting for the 10% code to work for that statue, since I would like to get the EX (won't display it with the EX but still, worth it for future value). However there is no doubt that Kylo will evolve looks-wise in VIII. He has the scar now, also left his helmet on Starkiller Base, and he is probably going to need a lightsaber that works properly. Not to mention the physical changes that follow a proper immersion into the dark side.
Regarding Vader, I will simply wait for in-hand pics/vids, given the ES and the lack of EX, I can just get one here in Europe from a retailer/eBay, it will be available for a long time undoubtedly.