As the internet film reviewer Confused Matthew said: "Worf basically does two things: either pontificate, or be publicly humiliated"
Sadly, it's mostly true. Often Worf pontificates with a clear divide between Right&Wrong; or he's publicly humiliated, especially when Picard has to remind him that it's not time to open fire just yet. How many times, if Picard had listened to Worf, there would have been a slaughter/interstellar war/diplomatic incident? Makes you wonder if you would want to put him in command of a starship in times of peace.
Yet, in other episodes Worf is less of a big Viking thick oaf, and more of a complex, troubled character. I think his being divided between his Klingon nature and his loyalty to the Federation is a great theme. Also, in some episodes his self-taught, VERY biased knowledge of his homeworld is treated very cleverly: for example, he tells Guinan that Klingons don't laugh, which is soundly untrue as she herself tells him. Then he's a stickler for formality and the old Klingon ways, much more than his contemporary Klingons: this because he's very attached to his native world, and he wants to honour it as best he can. There's also his pride in being Klingon that leads him to admit only with great reluctance that the Empire is corrupted. Not to mention his great sacrifice in Sins of the Father, when he accepts an unfair discommendation in order to save a (corrupt) Empire. These are very complex themes, and they make him a great, deep, tridimensional character.
But when he wants to shoot phasers at everything that moves, he gets pretty annoying and dispensable...