I also agree that Nathan East's part sounds good. And for that matter, that Anthony Jackson is a supportive musical player capable of using the extended range for good and not for evil.
But remember... the thing that started the conversation was someone's pithy assertion that "it's possible to suck way more on a 5 string than a 4."
And, while humorous, I do think that's at least somewhat true. An exceptional musician will find possibilities within whatever they're given. A less-exceptional musician, if given a bunch of extra 'stuff' (without having acquired the experience or understanding to know how and when to use those possibilities judiciously, or where to employ them) is typically (IMO, IME, etc) a worse situation than a limited player working within their means.