Danceofmasks: Depends on what you're trying to do.
If you're rushing for a heliotrope, armor rating can be largely irrelevant as you spam up your adrenaline, then hit the "I win" button.

The time slow bubble allows you to do whatever you want .. I like to slash with sword, but that's 'cos they can't get me and it's more amusing to get some vigor back.

There are also builds that don't rely on igni or heliotrope (though those are OP as all heck) ... such as the aard build ... which uses crit % and the time taken during the executions to regenerate vigor.
Sign damage is probably pointless in that scenario.