None, shes balanced as she is rn. Niche but extremely good in those situations, as she should be. But easily counterable hence her pickrate.
While i wouldnt mind seeing brig buffed back to what she was before the nerfs just to see the communities reaction because i love anarchy and chaos. Shes fine as she is rn
Mobility is fine. Mercy, lucio, moira has better mobility for healers. D.Va, Winston, Hammond have better mobility for tanks. Tracer, Genji, 76, Sombra, etc have better mobility for DPS. Plus her only mobility is shield bash, which is just 6m ish every 7seconds. 6m every 7 seconds isnt good mobility when you consider how her movement speed is reduced when she has her shield up.
SB range is 6 meters. Yes, people need to be “on point” but it s close combat. It s not that big. Majority of the roster have the range to operate outside of it. And in terms of “youre inevitably going to fight close range with her” the 7 second cd gave nearly everyone a long ish window of opportunity to attack brigitte while her sb is on cd.
It’s not her shield bash mobility that is the issue
Brig is incredibly fast especially when she can alternate between shield in lets than a second. this makes running away as anyone other than someone with vertical mobility really difficult.