Just a clarification, when I think about how hard I'm swinging I'm not thinking of it terms of arming or muscling the ball. 100% would still be an efficient swing utilizing the whole body, the kinetic chain, etc.
I've been doing a lot of rallying in the last year, not much serving or many sets. I've really been trying to work on my ground game, developing points, and finishing points (which I currently suck at). The two guys I hit with the most hit very hard. I'm swinging hard on each shot. It may not be 100%, but it's up there. But I'm trying to be set-up, balanced, and in control when I swing. It can be quite challenging, but a blast when it comes together.