Use Growing Power instead of Steel Charge. Very easy to use. Proc a status on something and cast Exalted Blade. Steel Charge's 60% damage is added to base damage mods, so it doesn't do much.
If you don't mind swapping mods, then the primed Smite mods are nice. For sorties you get the same faction three times in a row and for endless missions you have the same faction the whole time. Not so useful in Sanctuary Onslaught, and mixed faction on Lua (hardly a problem).
Is using Excalibur Umbra an option?
Other frames don't have Exalted Blade 😉
If you don't stay too long in those endless missions (sortie versions, for example), then you'll absolutely destroy those hordes with ease. For hours of endurance I'd indeed pick a different frame (try spamming E for hours, ouch!).