Sheet music and a performance is, of course, very different.
If I imported a score as MIDI into a sequencer I'd think about the emotional content of the song and what I wanted to portray and would tweak the rigid MIDI notes into a Human (as close to!) performance and then edit etc...
If you're wanting to print off the sheet music and have a real person play it on Piano for you it really depends on the players skill and individual style. You would have to explain the concepts and emotional content you want to invoke in the song. You could leave notes on the sheet music and work closely with the artist to achieve the sound you're after etc...
It's a very specific-to-the-project kinda task, if this is what you mean!