The specific problem of the 2008 financial crisis was that the banks were going out of their way to obfuscate the source of their CDOs so that, even when it was clear in 2007 that the subprime mortgage market was unraveling, you couldn't look at your instruments and figure out whether or not you were affected. The problem wasn't the CDO, it was the obfuscation. And as far as I'm aware, the current debt offerings aren't being obfuscated--if you want to avoid the data center debt because you think it's junk, just avoid the stuff being touted as data center debt.