As a Pentax DSLR owner, I would advise going with the a6000 over the smaller bodied Sony for most general shooting. The smaller bodies are really too small for use with a Pentax lens off a tripod. It is slightly better handheld with a focal reducer as the focal reducer is much shorter in length, but you'll need a FF, with an aperture ring, lens to use with it. I also was never was happy with manual focus with the LCD. With the EVF of the a6000, or the EVF of the 5n, I have no real issue nailing focus.
Coming from a pretty full kit with Pentax, I wanted a Sony system to do things that are prohibitively expensive with a DSLR. The first being an underwater shooting solution. There are <$200 40m underwater cases made for the Sony cameras, where to do the same in Pentax would cost north of $2000. Being able to use a focal reducer to use my Pentax FF lenses at almost FF FOV was also a pleasant development that happened a few months into my buying a Sony body.
I also own the DA 10-17mm that I bought new for less than the cost of a Samyang 8mm f3.5 fisheye in PK at a closing camera store, so I could never justify buying the Samsyang in Pk mount. I had less issue buying the really tiny Samyang 8mm f2.8 fisheye in e-mount, as it went on sale for $250. The choice between the Samyang 10mm f2.8 in Pentax or the Samyang 12mm f2 in e-mount was also a pretty easy decision as I have the Sigma 10-20mm in Pk.
As I didn't want to duplicate what I have with my Pentax setup, I bought the Sigma 19mm f2.8, Sigma 30mm f2.8, and Sigma 60mm f2.8 for the Sony setup as these are such a great value and fall between the primes I have for my DSLR. Each lens can be had for around $200. I added a couple PK to e-mount adapters to use the F and FA Pentax 1:1 macros I own to round out the rest of of what I wanted to do with the Sony setup. Well, I did buy an old manual focus 55mm f1.4 screw mount lens, as I also wanted to try the ~85mm eq FOV as well. I don't think I will ever buy the Da 55mm f1.4.
The only bonus to going with a smaller body would be had by buying a used Nex-5n. The 5n has electronic front curtain and with that and a Metz flash mounted on the 5n via a third party adapter, you can use any shutter speed with the flash due to the Metz flashes having 1/125s flash durations. All lthe way up to 1/4000s of the 5n. The a6000 also has electronic front curtain, but something has changed in the implementation where this sadly no longer works.
The small bodies are also really nice for macro use, and are really nice on a tripod. On the 5n I use a LCD screen shade and that helps with the sun issue. I also have the external EVF which offers the ability to flip vertically. Again nice for use with macros.
The small Sony bodies are really nice in more social shooting situations. Shooting via the LCD puts you more into the environment and less hiding behind a viewfinder. You interact more with the people you are with. If that is going to be your main reason for shooting with a e-mount camera, then the a5000 will be the better choice for you. You can sort of do the same with the a6000, but I just don't feel it is the same. I'm probably too tempted by the EVF not to use it, or I'm more conscious of not using it.
Thank you
Russell