Comma dangle

[jantimon]

Comma dangle decreases the quality of git-history and tends to cause merge conflicts as you have to change lines although you are not changing it.

The rule comes from >=IE7 because IE used to handle the comma dangle as syntax error.
For IE8+/Chrome/FF/Safari/Node that's not and issue anymore.

Do you see further benefits to follow this rules?
I would suggest to turn this rule off.

[easingthemes]

Still, it would be good to have some rule about it.

Maybe to use:
"always-multiline" requires trailing commas when the last element or property is in a different line than the closing ] or } and disallows trailing commas when the last element or property is on the same line as the closing ] or }

[jantimon]

Agreed "always-multiple" as suggested by @easingthemes is cleaner than turning it off

[smollweide]

Done: v2.0.0