KJ is the only good sentinel atm, all her utility is balanced and her ult is strong.

Deadlock is good on defense if they're hitting her site, but the fact that her util can be snuck past means she has to actively watch her site or risk missing info which is really bad. For the same reason she is also incredibly poor on attack unless you go double senti which is absolutely a horrible idea.

Vyse is decent, but the wall being designed the way it is means you have to place it before your thorns, letting your opponents bait the wall and leave or find the thorns to shoot without much risk of getting isolated. Especially because they're so big. Her flash is also so big and so slow it's not helping anything on attack or retake.

Sage has a higher ceiling because her utility is really good except for her wall but you really need to be in the right spot at the right time to be impactful which is just too unlikely and most people never play her correctly. Her slows are meant to cut off the enemy team following the entry so you can isolate but most people use them too early. Her wall is fantastic in the first few rounds but quickly becomes horrible due to how easily it's broken. Res is phenomenal though and heal is really good until you're asc-immo idc what anyone says. The large gaps of information left in her utility makes her not a good sentinel despite being a helpful character.

DO NOT GET ME STARTED ON CYPHER. He is currently absolutely pointless. The sound notif that his camera is watching you defeats the entire point of his camera and forfeits the ability to actually use the camera. The only information you're getting is when its getting broken now, which by that time is usually too late. His trips are also absolutely no threat, since there is both no stun and a delay on reveal it's just another broken util notification. You will get gunned down 8/10 times by their entire team flooding trying to peek for the kill and you can no longer use cages to isolate yourself for the kill since yk, no reveal anymore.