Oh interesting! I'm surprised you did so well with the double edged sword. I was afraid that people wouldn't like it because you can take some very heavy damage from boss encounters. Good to know that it worked well for you!
As units level up, they get to pick new abilities. I think the healer gets better with some ranged heals, but maybe they need to start with one so they don't feel useless. Good to know that you always go for the magic missile companions, sounds like the other ones need a buff!