He's an upgrade because he's an OF, and neither Kemp nor Wilson really are. Now, if last year is the beginning of the end for him that would be a problem, but his career production against LHP means something, and even if he's just neutral defensively (quite possible) that's an upgrade.
He's definitely an upgrade over Casty, which wasn't even suggested. We're more likely to see Rojas as our platoon LF than Casty if it isn't Kemp or Wilson.
But hey if the Bichette thing really happens not gonna see any new OFs either.
ESPN already downgraded their Bichette prediction to 150/5. Still a lot. I agree he's got warts.