Hold on a minute!Pay attention to this please..
There is a thing called musical taste.For example when i hear Paganini playing these crazy violin solos and staff i get excited.I dig into every note.Many people find that kind of playing (neoclassical players,Malmsteen,Jason Becker e.t.c) boring.For them to hear complex solos played fast is boring,they dont think it is melodical.My taste in music say it is melodical because it brings me an excitement and i like it.Take for example the harmonized solos and sweeps in speed metal symphony by Cacophony, the hair on my arms stand up from excitement every time i hear them.
Other people get this when they hear a slow nice melody.Everyone has his own taste in music.So you just cant say that this guitar player is really good but his compositions arent good.You just dont like that kind of music.
For example Dream Theater, some people like them some not,and it is natural,but you cant say that Petrucci is a great musician but his songs in DT suck..
I hope you get the point.It is all about what a particular music does to you.Mabey it does nothing to you but it sure does to someone else..