Looking at the current battlepass I don't think we will be getting any new agent or Map in next act . Also there is only 9 days remaining in the new act we saw no leaks from Riot so I think there will Agent changes coming this Act.
For these agent need Massive Nerf and Buffs
Agent that needs Buff are(Not including duelist as every Duelist need some buff except Raze and Jett) :-
Chamber(Remove Trap Range limit and Increase TP radius also Headhunter 100 creeds)
Fade(Once she has a good 50% + pick rate but now everyone started playing sova again)
Astra(Give her 5th star back)
Harbour(Reduce the High Tide cooldown and cove's smoke doesn't fade if the Shield is broken)
Cypher( May be Cam Tag Give a Decay )
Nerfs
Sova ( His recon should only scan for Once or max twice Like Fade one)
Killjoy ( may be adding a range to turrets vision)