I prefer Riot buffing weaker agents rather than nerfing stronger ones for balance changes simply to create unique diversity. Playing with reworked and buff characters is always more entertaining than sticking with ones that recently got heavily nerfed, and it also makes each individual agent more unique to their abilities.
Smokes: I don't think Astra or Viper need a nerf, but instead Omen and Brim need buffs. Omen needs a pretty decent rework for his ult, which I think is the weakest ult in the game. His smokes are barely unique to him except for the fact that they recharge very slowly and can sometimes be placed in certain wall spots. His TP seems the weakest (reworked Yoru TPs, Chamber insta-TP). Brim just needs a rework on his stim and he can easily find a niche to fill in.
Duelists: No duelist needs a nerf right now (yes even Jett). Phoenix obviously needs a huge buff/rework in all areas. His wall is simply inferior to Neon's, his flashes are considered the weakest in the game, the molly is only helpful in certain scenarios, and the ult is actually not bad. Maybe Reyna could get an extra soul orb to counter the phoenix buffs but I'm not too sure with this one. Yoru is already getting a rework, and Raze is good where she is.
Sentinels: Poor Sage is always getting nerfed ever since the early days of Valorant. Her heal should be buffed a little bit simply contend a much more powerful Skye heal. Killjoy is dominant enough, and Cypher should contend her spot by getting a better Cypher Cam or more tripwires. Chamber is fine where he is as of now (most likely going to be countered by the faster Neon playstyle we saw).
Initiators: I honestly think all agents in this field are fairly balanced and play their unique role. Breach, Kay/O, and Skye play a fair role in creating space and flashing for their teams, while Sova also provides extra info-gathering utility.
All of these are my personal opinions.
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