[Murdoko]

Follow your gut.

There I was with the Nikon Z5 (feels great BTW), Panasonic S5, and the K-1 ii which is relatively a dinosaur. I always drooled over the K-1 for some reason moreso than most other brands, but about as much as I drooled over the Fujifilm X-pro 2 which I ended up buying a year ago. Anyways, I'm waffling. The Salesman tried hard to convince me not to buy the K-1 pulling out cards like "it's a dinosaur", "mirrorless is the future", "you get a free Sigma lens if you get this", etc. Long story short, I held the K-1 with my medium-sized hands and it just felt right at home. I knew what I was getting into as I use MF almost exclusively; no EVF, big and bulky body (but it's actually a good thing when balance matters), and so on. I ended up buying a used K-1.

Again, follow your gut. Sometimes, the "logical" choice is not the right one.

[Wasp]

As far as I can see, used values for the K1 hold up quite well. Get one and use it. If it doesn't work out, the loss upon resale won't break the bank. You can think of it as a cheap rental deal.

I agree with @Rondec and everyone else who said stick with Canon. An APS-C camera will be lighter than your medium format gear, and mirrorless even more so. And I've been pretty noisy about my disapproval of Ricoh's customer support (or lack thereof), and I'd be remiss in advising you to do something that I wouldn't do (buy anything else from Ricoh).*

So my proposed solution is probably 90 degrees from what you're thinking, but I'd suggest the Canon 5ds or 5ds-r. Medium-format sensor in a DSLR body. Fantastic resolution and dynamic range. But about the same as carrying around the K-1 & its lenses in terms of weight and bulk.

* (I love the Pentax gear I've got, but that's after having spent an arm and a leg getting a bunch of new products fixed. And when it breaks, I may have it repaired but it won't be replaced.)

[normhead]

I hate to tell someone else what to buy.

My only observation would be you owned the K-1 and sold it.
Insanity is doing the same thing and expecting a different result.

[MJKoski]

Not really. Sometimes it is useful to try the competitive offerings only to realize they have even more issues.