He’s basically another skill-check character like Moira is. Unfortunately, the primary skill check is ‘teamwork’, which just isn’t something you’re going to random into more times than not (in solo queue bronze, for example).
At that point Bastion, like moira (and sometimes the other builders), becomes more of a solo-carry mechanical skill check. Unfortunately, it means you need basically gold skill to outplay a bastion that’s even remotely shielded/pocketed (in bronze).
The rework bastion mains talk about is giving him more utility during recon mode. I like that, and see him as more of a tank during relocation, body blocking and absorbing the brunt aggro a bit like a budget hog. Until, he sets up in turret-form and “takes space” through damage pressure and presence. Maybe throw him into the ‘would-be’ offtanks like mei and doom. Lower his dmg and up his padding? Nothing is saying an offtank can’t do their job through damage and zone clearing threats.