For me, it depends on your officer and the skill of the linesmen. If you have a good officer leading you and everyone knows where they are supposed to go and what they need to do, volleying and doing formations quickly while dodging bullets is tense, gratifying, and a hell of a lot of fun. On the other hand, if you have a leader that is unsure or incompetent, or you're in a line full of recruits, you'll just be bumbling around in a blob as you get riddled with bullets. Melee is always fun, even if it's you and some people that only discovered what a computer is against the best of the 12th, it's still fun.
Every once in a while, you get one of those perfect, deeply satisfying rounds of volleying or a well executed formation, but unless it's extraordinary, non melee action can get dull, fast. So on average, I'd say that melee is by far the most fun part of a linebattle, and I'm glad it had such a focus.