Having read and skimmed several articles in legal journals, but not being a lawyer myself, my impression is that many law review articles are long-winded, using many words and sentences when fewer could convey the same information. Do lawyers and legal scholars feel this way as well? If so, what reasons do they give to explain this situation?
Law doesn't have a monopoly on bad writing.
Steven Pinker, in "Sense of Style" and other articles, says that the kind of poor writing you mention is a symptom of the "curse of knowledge".
Justice Kagan believes that good legal writing needs to at least be good writing, and law schools aren't doing enough to teach that. All the other Justices expressed similar opinions to that in interviews with Bryan Garner.
I think the underlying reason is the requirement (somewhat shared with philosophy) to be exhaustive, i.e. cover all perspectives on a question and all relevant facts. Short articles narrowly focused on hair-splitting minutia might cover all of the case law and legal literature within a few pages, but anything that takes on a massive topic like "what does 'literal truth' mean in perjury case law?" will have to cover very many cases. One of the reasons is that while Bronston v. US is the "leading" case on that topic, it is not the last word, and there have been some interesting subtle developments after that. Gathering up that case law in one place is thus very useful.
At least in common law jurisdictions, where judicial precedent forms a large part of the way the law works, the authors of academic or review articles are often at pains to avoid appearing to prejudge any issue, while at the same time seeking to get their own interpretation of the ramifications of some quirk or novelty of the law across to a wider readership. It is important for several reasons that this is the case: firstly, that authority in law belongs to the legislature and to the judiciary and not to academic writers, on whom it is impressed throughout their training that the word of the judge is final and that judges are to be persuaded and not to be told what to do; secondly, that because of this academic writers tread a narrow line where their opinion must be clearly based upon the known precedented facts of the law as it is known and understood to stand while simultaneously expressing a didactic opinion that may at the time have little or no legislative or judicial support and indeed lack any evidentiary basis, for which they depend on fully-explored hypotheticals which usually take some explaining and hedging and qualifying; thirdly that every academic hopes that someday their work will be quoted approvingly in court, which is unlikely to happen unless it is couched in language that the court will find acceptable.
More briefly: an academic writer is neither a judge nor an advocate. They can't lay down the law or be seen to be trying to do so. So they wrap up detailed arguments in ifs, buts and maybes, partly through training and partly through traditional deferral to the judiciary as the real arbiters of the law.
It's quite instructive to read different things written by the same writer, you'll find they are much more prolix in academia, and much more succinct when arguing before a court (which is a situation where they are both allowed and expected to express robust opinions)
The customary length of a law review article is to a great extent a matter of tradition and historical issues like length limitations.
There are many people who believe that law review articles are too long, and indeed, law review articles are quite rarely cited by courts or lawyers, although they are fairly often used to locate cases on points relevant to the article. There is a weak movement in the legal academy to change this trend, but tradition is a powerful force and there is a strong normative belief in the legal academy that a law review article should be exhaustively complete and definitive.
One of the most famous examples of the sparring between the judiciary and the legal academy involve a hypothetical law review article mentioned by Chief Justice Roberts and the law professor who retroactively wrote it (incidentally, the law professor was himself quite conservative as law professors go, this wasn't simply a matter of partisanship). The abstract of the rebuttal article (which is contrary to tradition and precedent just three pages long) is as follows:
In 2011, Chief Justice Roberts commented that if you "pick up a copy of any law review that you see," "the first article is likely to be, you know, the influence of Immanuel Kant on evidentiary approaches in 18th-century Bulgaria, or something, which I'm sure was of great interest to the academic that wrote it, but isn't of much help to the bar.” No such article exists, of course -- until now. This short essay explains why, in all likelihood, Kant’s influence on evidentiary approaches in 18th-century Bulgaria was none.
Orin S. Kerr, "The Influence of Immanuel Kant on Evidentiary Approaches in Eighteenth Century Bulgaria" (March 28, 2015)