McGrath, a guitar can be used as a melody instrument in an Irish session as well as a rythym instrument. I am not quite sure what you mean by "flashy and obtrusive". I have played in several sessions where a SLIGHTLY dominant rythym player (guitar and bodhran) has actually helped to pull a session together. I have also played with guitar players who play all sorts of fancy chords up and down the neck and bodhran players who have done clever bits and it works well.

The main point is that a player needs to be skilled and have feeling for the music, and for other players before attempting anything beyond the basics.

Jon