I've a set and never had a problem with them except that the AF540FGZ doesn't want to work on them like it should but other flashes work without a problem.
I've contact the manufactures about that and they were most helpful and offer even a cash back but it's cheaper to buy a new flash then to buy new triggers so i did that.

It's only 150 gram lighter don't think you will really notice a big difference there and the size is roughly the same.

The thing is the K5 and K7 have a lot off buttons to access features directly but the Kr is pretty much menu based so the Kr will work differently than the camera's you've now.
Just saying so you know what to expect.

Do you actually need a second body?
Why not sell the K7 and spend the funds on a lens?

What lenses do you've and where do you use them for?

Yves, already knew that one, amazing how it can "stand" on only two wheels.
Not much use in the snow though

I had the feeling it would be but couldn't find it so fast in your first link when i clicked on the video.

It actually tells pretty much the same story has Peter did but I'm glad his comment helped you.

Very strange though that it won't fire as master but does so when set to controller.
You sure the channels and settings were correct.

Might this be something for when it snows?

That's also an option.
Or ask for less range and go for a 17-70 lens, those are also perfect walk around lenses and are maybe more pleasurable to work with.
The only thing you're missing is the ability to shoot wild animals but you can always get a XX-300mm lens for that.

It's harder to find the lens.
Why not opt for a two lens solution?
DAL 18-55 with either the DAL 50-200 or DAL 55-300 ?

SDHC is already old get an SDXC reader so that you can also read the current cards

The current standards ISO 2720:1974 and ANSI PH3.49-1971 for light meters are from the 70's

They might if you've registered the lens for worldwide warranty.
Gwyn knows more about that.