Using the adverbial connective however (see "Banish Stock Transitional Expressions") is not an outright stylistic weakness but a device useful, even necessary, in speech, hence in fiction, a device, though often excessive, that persists because of over close identification of competent speech and writing. Characteristics of speech demanding artificial connectors are its short sentences and explicit signposts, so nonfiction writing calling for short sentences and signposts can warrant using adverbial connectives. Writing requires short sentences and signposts when it demands hyperclarity, as for legal briefs in our overcrowded courts.
Some statistics help in grasping the size of sentence-length differences. Many essayists write sentences averaging 22 to 28 words. Bryan Garner recommends sentences in legal briefs average 20 words. Plain-language advocates typically call for sentences averaging 15 to 20 words. Many excellent fiction writers seem to average around 18 words per sentence. (Hat tip to StevenBerlinJohnson.com, where you can find some surprising statistics and observations on writers' sentence lengths.)
If clarity demands only moderately shorter sentences, as in brief writing, occasionally starting a sentence with a coordinating conjunction, such as and or but, is a less distorting method of artificial connection than adverbial connectives, such as however, moreover, nevertheless, and in addition, terms depicting relations between referring clauses, not referenced objects. To appreciate why initial conjunctions are less distorting than adverbial connectives, it helps to understand the connective paradox: when they begin sentences, these so-called conjunctions function as adverbial connectives. A coordinating conjunction at the beginning of a sentence doesn't tie the two sentences together, sometimes advertised: it doesn't function like a semicolon to establish a relationship stronger than separate sentences but weaker than conjoined coordinate clauses. The reader, having read the sentence complete, can't undo the perception, so but no longer functions conjunctively. But takes the meaning of however and comes to exemplify the same lexical category. But always has an adverbial component; otherwise, it couldn't assert contrariety. Dropping the conjunctive component by using but at a sentence's beginning leaves only a light-adverb remainder.
When exceptional circumstances don't limit sentence length, the writer can be more precise by striking the initial conjunction, combining the sentences to turn the initial conjunction into an ordinary conjunction, or rewriting. George Orwell disagreed. Here's an example including an initial conjunction, but, and an adverbial connective (or stock transitional phrase), on the other hand, from George Orwell's essay "Politics and the English Language":
A newly invented metaphor assists thought by evoking a visual image, while on the other hand a metaphor which is technically 'dead' (e. g. iron resolution) has in effect reverted to being an ordinary word and can generally be used without loss of vividness. But in between these two classes there is a huge dump of worn-out metaphors which have lost all evocative power and are merely used because they save people the trouble of inventing phrases for themselves.I would rewrite the passage by eliminating the transitional phrase, using but to connect clauses within one sentence, and replacing the compound predicate reverted... and ... used with a simple predicate and adjective phrase, thus:
A newly invented metaphor assists thought by evoking a visual image, while a metaphor which is technically 'dead' (e. g. iron resolution) has in effect reverted to being an ordinary word, generally usable without loss of vividness, but in between these two classes there is a huge dump of worn-out metaphors which have lost all evocative power and are merely used because they save people the trouble of inventing phrases for themselves.The transitional phrase on the other hand helped convey that Orwell mentioned the newly invented and the dead as opposite statuses for metaphors. Joining the clause about the worn-out metaphors with the previous sentence, containing the contrast, makes the same point about opposite statuses without using the transitional phrase on the other hand. The clause about the worn-out metaphors introduces the opposites by locating worn-out metaphors between them. The sentence is longer than any of Orwell's, but the passage gains precision using fewer words.