No ability to change line thickness as of the 7.0.68.7827 Beta version.
You can change colors from the default colors. I found the default CHA blue was the same color as too many other things on the screen, so I changed CHA to a brighter blue. Other channel default colors work for me.
Rest assured this will be part of PS7 as we move forward to parity with PS6
It has not been forgotten and will be included in future builds
I have just added your comments to an existing request for the software team to triage accordingly