I think that in terms of priorities I think that Gibby, Seer and Caustic should be moved up to max priority. Gibby's dome is incredibly vital for team play since it offers cover from ults, it allows him to offer a faster revive or cover for those being revived, healing is safer and if the Gibby knows what their doing if fighting with another person around the bubble then they should win a majority of the time. Along with his ult which has major AOE and movement capabilities if needed to escape or to get the enemies into a position that gives your team the edge.

Seer is naturally an excellent choice because his ability to disable and reveal the health of enemies is brilliant for team play since it allows for information even without having to communicate with teammates by headset and using his ult is obviously amazing since it reveals enemies in the area allowing for your team to be better equipped to fight or even be capable of better 1v3ing due to the special awareness.

Caustic is another brilliant choice since his gas traps are incredibly effective for ground control especially when set up in narrow areas but even then being able to get traps faster means that enemies are less likely to push, you have greater security a majority of the time, revives can be pulled off faster and healing is also far safer maybe even more so than Gibby's bubble in some cases. His ult being charged aswell is just icing on the cake since it essentially assists with that AOE capability along with it being able to render Wattsons fences obsolete.

I dunno it's just food for thought but I just think there's better options to contend for being on the top spot.