How do you straighten edges ?

Drop down a Sculpt node, move your mouse into the 3D window and press enter. This should put you into paint/brush mode. Right-Click and choose Smooth instead of Displace for your mouse action. Now you can paint over top of the mesh and smooth out the edge lines. The lines will generally conform to the direction you generate the brush stroke in.

This sculpt/smooth technique is demonstrated at around 12:00 in this video.
https://vimeo.com/172970210 [vimeo.com]

Edit Straighten
https://vimeo.com/167151984 [vimeo.com]

That is excellent, really great modeling tools.

I like one thing which I hope H16 solves, is condense multiple tool functions in one node, as is the edit node, for modeling is a key issue.