Crusader armor relic perk, or ANY bonus you get after an execution. It sounds good.. 

But the only enemies you can execute are elite enemies. 

Elite enemies are nearly always the last one standing. 

Therefore the perk is useless, as you'll never get a chance to use it. There's never anything left to kill for you to use it. 

Now you might think you have a chance to use it in multiplayer, but executions don't seem to work in multiplayer. 

And let's be honest, if by some miracle of chance it actually happened, how useful is it really? To mop up trash mobs that you can pretty much one hit kill already? 

Relic armor bonus needs to be worthy of the status of the armor. Increased loot drop, or some passive perk like +5 warfare etc 

*shrugs*