Great guide Vanguards. I'm not quite sure how Justicar's Vengeance works but i still think the other two options are really good in certain situations as you mentioned.
Justicar's Vengeance takes 5HP to deal damage and also heal you for 100% of the damage dealt. It does double against stunned targets - useful for some extra healing on yourself while doing damage especially when you can use a divine purpose proc + using it on a stunned target.
Updated for 7.0.3. Patch is early and many things are still being tested. Please feel free to comment on any of the choices I made.
My general feel for Rets in this pre-patch is they're relatively underwhelming and mobility seems to be a huge issue. However, it's still quite early and artifacts + Honor Talents will change the game a lot in Legion.
This should be fixed now, there might be a chance your gladiator / rank 1 helmets were affected. If any are missing feel free to post it in the glad helmet post in the same forum using the provided format and I'll look into it.