It is really a shame that Amazon and its publishers are forcing full justification on us. It should be an option. I'd choose to always use a ragged right.
There is a thread in the developers section that details how to get the justification dialog back on the DX. It should work with the K2 as well. There is no bin file so you'll need to get the USB networking hack working first and manually make the changes via ssh.
https://www.mobileread.com/forums/showthread.php?t=51582
Regards