He was definitely worse than Barton last year. Bush didn't have really any redeeming qualities, and is also hated by Steelers fans like Barton was hated here.
Barton gets the whipping boy treatment, but he actually was a decent player in coverage. Barton's issues were with disengaging from blocks, which he is genuinely bad at, but he also didn't have a lot of assistance as he always had guys getting to him at the second level immediately due to bad run fitting.
Brooks was also suddenly awful last year. It was almost certainly a systemic failure more than a bunch of individual failures.
I've made this point before, but I think it speaks volumes that one of the better defensive coaches in the league who made his name as a linebacker specialist snapped Cody up immediately in the first wave of free agency. There's more redeeming there than people give credit for. He's unspectacular and preferably not a starter, but he's not the worst linebacker around.
Barton is probably going to look league average, maybe even slightly above average, if the line in Washington does a better job at keeping him clean.
Bush is physically gifted but has been absolutely dreadful since his rookie season. He can provide depth at the spot and is a legitimate reclamation project. I like the signing. I won't be surprised if he improves markedly, and I also won't be surprised if he doesn't even make the roster.
TL;DR: Cody Barton wasn't a spectacular failure, and Bush is just as bad (probably worse) but is a great candidate to improve.