songwriting is a big deal to me. because im in a ska band with horns and whatnot, and im usually the one writing the various riffs and runs in our songs, i have to think of more universal melodies rather than just on guitar. alot of great songwriters have used piano as their inspiration to write peices on guitar. i mean, a guitar is essentially a rudimental piano, with alot more nuances and imperfections than a piano (not necesarilly a bad thing). i personally suck at playing the piano, but youve got a leg up on many guitarists if you are a good pianist. understanding simple things like adding 6ths to your major scale run is much more difficult to understand and comprehend on a guitar as opposed to a piano, were youre looking directly at a string of repetitions up the keys. bla bla bla, long story short, good for you. no, its not a bad thing that you write music like that; it could only be more benificial.