I think the real objections would be things like (and I'm not necessarily saying these are true/false, just that they're the ones that people should really be thinking about):
* Are NoSQL databases the object databases of the modern era?
* Is our pain big enough that we're willing to be a guinea pig for any new technology?
* How will making this technology choice impact our future ability to hire and to work with future technologies?
* Is this the right time to adopt a new database, or will the world be so different in 3 months that we should limp along until then?
From my viewpoint (@ FathomDB), that last point is the most interesting. We're seeing the start of NoSQL convergence; I expect both rapid development and serious teething issues. We see FathomDB & VoltDB announcing early availability of scalable relational databases. Rackspace hired the core of the Drizzle team, so this project will likely start to bear more fruit. To borrow from the wife-selection problem, it feels like immediately getting married to the first attractive person you meet on your first day at college, when there's a freshman mixer that evening.