I've been looking at Fuji these last few days myself. But it's not the camera I'm so interested it, it's the lenses. I think the X-T1 is just the body I might get to go with them.
The 14/2.8 and 23/1.4 look excellent. And the upcoming 56/1.2 as well. At least those are the ones I'm most interested in. The 60 macro looks good too, and the 35/1.4 looks good for the price.
They do have the best kit lens I've seen (18-55/2.8-4). And the 27mm looks pretty good, especially for $200 right now (though I'd opt for the significantly more expensive 23).
Just keep in mind they only have one realistic option right now on the long end, the 55-200 at $500 (I realize they have a 50-230 as well but it's slower and it's only $100 less right now). And it's not all the fast in aperture either, compared to constant f/4 and f/2.8 zooms from other makes. But I'm sure the IQ is still fairly nice.
The point is, you'll be investing some real money in lenses, and the selection is rather limited, so you have to be happy with the 18-55, 55-200, and primes no longer than 60mm for a while (unless you count 3rd party lenses like the Samyang (Rokinon) 85/1.4 MF lens).
BTW, your current lenses don't even begin to exploit the potential of the K-5 II.
If you
do try a Fuji system, you'd probably be better off getting a used body or a new X-E1 bundled with the 18-55 lens for only $200 more. Then order the 55-200 with the current instant rebate and choose 1 or 2 primes you'd like to try (all of them look good for the price, except the 18/2 where the more expensive 14/2.8 just seems a better use of money for the IQ). So for example, if you're trying to be semi-economical, you might try the 27 or 35 and the 60 macro.
Regardless of which system you choose, you need to be looking at better lenses right now, not better bodies. The Pentax will let you grow your lens kit much more - for example you should be looking at adding something like a used DA*50-135 and budget macro (e.g. Cosina 100/3.5) right now. Much better than dropping $1300+lenses ($1500 minimum with only the 27mm) on a X-T1 right now. But if you want to keep it simple and grow at a slow pace (actually, be forced to), the Fuji offers nice options.
The only reason I was considering a Fuji is I've been wanting better landscape photos. But I've been carefully studying the Pentax Photo Gallery tonight (which you should too if you haven't:
PENTAX : Select a PENTAX interchangeable lens camera or a lens model) and I think I see what I need to change to get better photos with my existing lenses. Believe it or not, part of it entails going back to my older K200D with certain lenses.
Sorry, rapidly depreciating camera bodies don't excite me that much. I want the cheapest one that will do the job (which, unfortunately,
sometimes still requires an upgraded body) that I can attach my nice lenses to.