The accelerator unit is not just for ooc JPEG but RAW as well:
Is this describing what the accelerator unit does? - PentaxForums.com
That's why some prefer the K1 over the K1II, the K1 does not have it.
About the solenoid:
The danger is now much less than it was with the K30, pre Dec.2015 manufactured K50/K-S1/K-S2:
A LITTLE BIT OF HISTORY: Development of the solenoid in Pentax cameras - PentaxForums.com
and if ever the odds would be stuck against you and the solenoid of your K70 would fail, you could prepare by:
- paying with credit card and use it's protection
- paying a little extra for a 5 yr. warranty
- study if you would feel confident to the pretty easy DIY-repair:
Tutorial/Repair Pentax K-70 with aperture-problem: Exchange solenoid - PentaxForums.com
But I understand the TO very well concerning the way the K5 feels in one's hands, to me the K5-Series (and K7) was the best ever just for handling.
Also the direct access was almost as good as with the K10D and K20D.
With the battery-grip the K5-series felt utmost solid and well balanced like no other Pentax to me (I had the K3, K70 and have the KP but kept a K5II which will stay with me....). The K30/K50 I found second best but they missed important features which the KP does as well but then it has other features.
Because I just love the DA55-300PLM and at times just walk with it alone or a DA21 or DA15 in my pocket I'd chose the KP or K70 for a new body.
But I could live very well with the K5IIs and then shed a tear for not being able to use the PLM any more.
If the K5-series would have gotten the KAF4 firmware update, I would at times prefer the K5IIs over the K70 and KP because I know that except cropping I will get
as good quality photos with it than with the K5IIs (and partly K5II). So the K3 or K3II might be another option but it is that bit larger than the K5series but they accept KAF4/PLM.