K-1 is an impressive camera and it is good for landscapes.. but, in considering K-1, you aren't making a decision about 'pro' or 'beginner' type camera... rather, you are making a decision about format meaning APS-c or full frame.
All the comments about starting with a used beginner camera or starting directly with flagship are fine. I think you need to first decide if you will even want FF and to THEN worry about type of camera.
There are people who don't want FF for macro and animals. They have good reasons. FF isn't necessary for landscape. FF or APS-C will shape the decisions you make for lenses. Decide sensor format first. If you are unsure, I guess get a competent APS-C and let things perk a bit
I was real happy with my K-5 but bought a K-1 for my reasons. For what I do, the K-5 was great and smaller.. I do like the smaller size and had to make trade offs for traveling to offset the extra weight. What will you do with your camera stuff... just a thing to consider :^)
For 'pro' camera features, I would recommend K-5iis (not K-5) or the K-3 series and the K-3 should have better AF and greater pixel density that should be nice for landscapes. You may find the K-3 loses a bit to dynamic range (in tests) but I don't think it is significant and if you aren't very careful with exposure, you will lose more there than with the difference between K-5 & K-3.
For not 'pro', other camera models have been mentioned. You can do almost all the same with these basic cameras. Certainly you can do all the same typical picture taking exposure stuff but you may need a few more button presses or dial turns.
If you are technical and like fooling with things and learning things and 'configuring things/apps, I would not worry a bit about being intimidated by 'pro' buttons and whatever on cameras. If you are not into this stuff and just like simple interfaces with the things you own, button mania might be a thing to consider :^)
However, as I first wrote, you are really making a format decision. 9 months ago, 'pro' or not APS-C body was the only consideration with Pentax. Now you must first decide FF or not. If you want FF and Pentax, the body decision becomes simple, yeah ?
---------- Post added 10-30-16 at 01:32 AM ----------
Originally posted by FantasticMrFox Why do you associate beginners with auto mode? Anyone who wants to get into photography should start learning how to do proper exposures in various modes, we shouldn't encourage people to use auto mode just because they are beginners.
Yeah, there was a time people had to learn with either aperture or shutter priority being the only 'auto' mode. And they managed it. Digital and the instant feedback it provides is really nice.
'auto' everything can make the camera more like a point and shoot.. but I think starting with a priority mode like Av or Tv is not a bad thing.
---------- Post added 10-30-16 at 01:50 AM ----------
Originally posted by Ash Advanced cameras like the K-1 allow a budding photographer room to grow into it. ...
I never used most of the electronic features of the K-5...
Bracketing only some. Shutter delay or mirror lock up more.
Bulb mode some and multi-exposure a couple times
Center point AF with manual point select only.
All the other stuff (HDR or focus point groups or horizon tilt or whatever else the camera does) is not used. The K-1 offers even more features and I expect to use even fewer of them :^) I don't take pictures of very dynamic subjects.
I did use K-1 5-point group select AF of whatever to take a picture of a llama. I think I will like this and some other bits of new AF tech in K-1. Should help with sheep pics. Otherwise, I really use the 'pro' bodies in a pretty basic way..! I like two command dials.
Of course, none of this changes your valid comment about room to grow. I just realized how few features I use. I ignore the features I don't need and the complex body is simple enough.