Can you expand on what's wrong with declarative design? I'm not talking about UML, but modeling specifically. Since I've been doing it for quite a few years I

Can you expand on what's wrong with declarative design? I'm not talking about UML, but modeling specifically. Since I've been doing it for quite a few years I guess I know a thing or two about MDA/MDE. And it's not about disdain for writing code.