These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Without Remorse is a revenge fantasy about drug dealers, set during the Vietnam War. The protagonist, an ex Navy SEAL named John Kelly, runs afoul of a drug ring run by a man named Henry Tucker. Tucker smuggles high-grade heroin into the Baltimore area inside the bodies of American soldiers killed in Vietnam. He distributes the drugs via a stable of prostitutes that he controls using drugs, rape, and torture. When one of his girls escapes and befriends Kelly, he has her kidnapped, then rapes her, tortures her, and mutilates her corpse, forcing the other girls to watch, before dumping it in a public fountain. As Kelly tracks him down while murdering his people, he grows increasingly desperate, going so far as to kill his own associates out of paranoia, then attempts to kill his remaining girls when they prove to be a security risk. In the end, he is shot down like a dog without pity, and even the police admit that Kelly did something that they themselves might have done were they not bound by the law.
Patriot Games gives us Sean Miller, leader of an Irish terrorist group. The book begins with Miller leading an attack on the British Royal family. After being stopped, Miller goes after The Hero and CIA analyst Jack Ryan and his whole family, causing the car with Ryan's daughter Sally and pregnant wife Cathy to crash. With other various acts of terrorism to his name, one incident from Miller sticks out. When in prison, a guard saves him from Prison Rape from other inmates. During his escape, Miller has the guard at his mercy and chooses to shoot him in a way to paralyze him for life, viewing it worse than killing the man and declaring gratitude is a "disease of dogs," quoting Josef Stalin.
Ensemble Darkhorse: John Clark, who is probably Tom Clancy's most popular character (even moreso than Jack Ryan).
Harsher in Hindsight: In The opening chapters of Command Authority, a Russian operative says that the Russian President Volodin will order the Russian military to invade Ukraine and annex the Crimean peninsula. The novel was published in December of 2013. Three months later, Russia invaded Ukraine and annexed Crimea, using similar methodology to the book invasion (imported "protesters" used as a causus belli).
Nightmare Fuel: Though Clancy points out in his afterword to The Sum of All Fears that he specifically changed a lot of details on creating a nuclear bomb, he also points out that the information necessary to do so is public knowledge, and not terribly difficult to acquire.
Sequelitis: Ever since the end of the U.S.S.R as convenient baddies and as the books' discussion of US Politics, some feel the books have become more of a platform for Clancy's conservatism, at the expense of story.
David Letterman once joked about this, when revealing the new Tom Clancy novel was titled, "Please, please, please let the Russians be bad again."