I brought Niles for the chests on the Rainbow Sage map, but his bow was given to Mozu and he just paired with Azura to boost her stats. Then Kaze replaced him for that purpose for a little bit, then I just brought Shura along for any future chest maps.
Having to bring a unit I didn't use just for Locktouch was a mite annoying, but I soon found myself with enough extra spots to just bring one along without issue.
The thing about Live to Serve was, usually the healers take more damage than the targets they're healing, so if I didn't have multiple targets to heal I'd still have to have my second healer heal them anyway. Both also had to fight from afar and stayed well away from enemies like Ninjas, so they didn't often take hits in the first place, especially once Felicia became little more than a stat mule for Ophelia and an aura provider from the level 15 Strategist skill and Demoiselle. Tomebreaker was quite useful for Felicia since she has lower defensive stats and it let me pass it on to Ophelia to make her a powerful anti-magic unit, and it made Great Knight Jakob into a mage-murdering machine in Birthright, but Elise barely took any magic damage to begin with. Enemy Onmyoji were one thing, but the spell-slinging Oni Chieftains peppered around the final chapters couldn't even scratch her with their magic.
