Usable without a shield. Only trade-off is shared cooldown with Overpower.So I suppose it may be useful for any warrior, that does more damage with revenge than overpower, and actually even as arms warrior, you will be geared in epics, before it comes tho this.
While revenge was quite useless as damage ability in previous expansions, I was interested in using it in non prot warrior builds.
I would not recommend sitting in defensive stance and mashing revenge keybind, unless you have an according spec, and definetly wont if you are not wielding any shield. Yet taking advantage of occurring dodges and parries, you have to know when they happen.
Unfortunately most addons that show procs and events are configured only from the stand point of a tank in regards of using revenge, only show it in defensive stance.
Solution I found (from old Wowhead comments) was to use an addon: Mik`s Scrolling Battle Text.
Most of you are already familiar with it, since its legacy spans from TBC, yet here its highly customizable and is already full with ready presets.
Find revenge trigger, press configure and remove exception for defensive stance only.
Change sound alert for something unique
Create and change output area specially for this event.
* I prefer static appierance in the middle of the screen, with most features of this addon disabled.
While this may appear as unnoticeable gain, as warriors ussualy have 5-8% parry/dodge, it works extremly well in pvp where you are forced to stay out of defensive stance.
Also I should add that revenge will not work as good vs dodgy classes (comparing to overpower), but most likely devistate cloth wearing classes, so if you see Revenge proccing don't be shy and switch targets.