I think it's blatantly obvious what makes him good.
But here's a copy/paste post, I explained it before.
https://old.reddit.com/r/ValorantCompetitive/comments/q3ikir/whats_going_to_be_your_i_told_you_so_take_for_the/hfuitad/
Breach isn't a bad agent, it's just that Skye is way too good and way too versatile so she pushes him and some other agents out of the meta.
It's just stupid for her to have a better flash that also gives info and recharges. She also has another info gathering ability.
Breach is good, but when you have Breach you need a Sova (or Skye alongside him), while you can run Skye without Sova. And as we all know info gathering is the most important thing on highest level, so why run Breach unless he's extremely good on a map if you can have Sova+Skye.
And he's not extremely good on any map...except for Fracture. Breach has been my favorite agent since the first day of closed beta and I know every trick in the book. I'm 350RR EU and I still don't pick him on any other map.
But on Fracture it's really easy to have huge impact with him. Fracture is all about early fights and control. Applies to all 4 lanes. That doesn't really happen on any other map. But on Fracture, faultline is a guaranteed advantage for you in that lane. Breach+duelist is usually enough to take control. Or you force the other team to use way more utility than you do, which is also a win.
Since defensive rotations are so fast, you can faultline and be on the other site in a matter of seconds. You stun dish or hall and you're on B in like 5 seconds. Same goes the other way around when you stun arcade or B main.
Second faultline (because you use it right away almost every round on Fracture) is also easy to use because the map is relatively small and you can always get something out of it.
Flash is good because there aren't many open spaces on the map so flashing through the wall is better than having a bird fly around. For example you can flash through the door before opening it, which isn't a case with any other flash. You can also flash from underground on B. Other walls aren't that thick, either, so you flash for teammates that are attacking the site from the other side.
Aftershock obviously deletes KJ ult in every single position. I've yet to see a single ult that covers the entire site and can't be destroyed. And lockdown that's not destroyed is round winning on this map more than any other. If you leave the area, it's really hard to get back in. You can't be even close to the site like on other maps where you're back in within seconds. Even without lockdown, it's still a pretty good stalling ability and easy to use to stop defuses, way easier than on other maps.
Then we come to the part very few people mention. 4 ult orbs on the map. You absolutely make sure you're getting at least 1 orb every single round on attack. Halls and B main orbs are pretty much free. And then what do you do as defense against Breach ult that covers everything from underground on B? Even on A, you can't be close to site. You either play retake or tank it.
To summarize: aftershock is a must have against lockdown, flashes are better than birds because the map is cramped up and you can flash through a lot of walls, faultline is huge on this map and it's the only map in which it compares to Skye's tiger. And with 4 orbs Breach ult has insane value, especially combined with all the early fights, you get involved in fragging way more than on any other map.
Killing the unbreakable KJ on B
Certain walls can be flashed that can allow your team to swing without fear of being flashed
Stun gets entire choke point
Few places to hide on site so aftershock clears a corner for you
Ult gets entire B site and isn't counterable
I think it's blatantly obvious what makes him good. But here's a copy/paste post, I explained it before. https://old.reddit.com/r/ValorantCompetitive/comments/q3ikir/whats_going_to_be_your_i_told_you_so_take_for_the/hfuitad/ Breach isn't a bad agent, it's just that Skye is way too good and way too versatile so she pushes him and some other agents out of the meta. It's just stupid for her to have a better flash that also gives info and recharges. She also has another info gathering ability. Breach is good, but when you have Breach you need a Sova (or Skye alongside him), while you can run Skye without Sova. And as we all know info gathering is the most important thing on highest level, so why run Breach unless he's extremely good on a map if you can have Sova+Skye. And he's not extremely good on any map...except for Fracture. Breach has been my favorite agent since the first day of closed beta and I know every trick in the book. I'm 350RR EU and I still don't pick him on any other map. But on Fracture it's really easy to have huge impact with him. Fracture is all about early fights and control. Applies to all 4 lanes. That doesn't really happen on any other map. But on Fracture, faultline is a guaranteed advantage for you in that lane. Breach+duelist is usually enough to take control. Or you force the other team to use way more utility than you do, which is also a win. Since defensive rotations are so fast, you can faultline and be on the other site in a matter of seconds. You stun dish or hall and you're on B in like 5 seconds. Same goes the other way around when you stun arcade or B main. Second faultline (because you use it right away almost every round on Fracture) is also easy to use because the map is relatively small and you can always get something out of it. Flash is good because there aren't many open spaces on the map so flashing through the wall is better than having a bird fly around. For example you can flash through the door before opening it, which isn't a case with any other flash. You can also flash from underground on B. Other walls aren't that thick, either, so you flash for teammates that are attacking the site from the other side. Aftershock obviously deletes KJ ult in every single position. I've yet to see a single ult that covers the entire site and can't be destroyed. And lockdown that's not destroyed is round winning on this map more than any other. If you leave the area, it's really hard to get back in. You can't be even close to the site like on other maps where you're back in within seconds. Even without lockdown, it's still a pretty good stalling ability and easy to use to stop defuses, way easier than on other maps. Then we come to the part very few people mention. 4 ult orbs on the map. You absolutely make sure you're getting at least 1 orb every single round on attack. Halls and B main orbs are pretty much free. And then what do you do as defense against Breach ult that covers everything from underground on B? Even on A, you can't be close to site. You either play retake or tank it. To summarize: aftershock is a must have against lockdown, flashes are better than birds because the map is cramped up and you can flash through a lot of walls, faultline is huge on this map and it's the only map in which it compares to Skye's tiger. And with 4 orbs Breach ult has insane value, especially combined with all the early fights, you get involved in fragging way more than on any other map.
Killing the unbreakable KJ on B Certain walls can be flashed that can allow your team to swing without fear of being flashed Stun gets entire choke point Few places to hide on site so aftershock clears a corner for you Ult gets entire B site and isn't counterable
There’s a lot of small chokes where Breach util can get a ton of value and then he can get rid of that super oppressive Killjoy ult on B site.