The major problem with Agile is that it is the new software development buzzword, and thus is perceived as a golden bullet for software development. Agile has a specific application: development of experimental software, where the project sponsors know they need something in a particular area but do not know exactly what. Agile (and iterative development in general) lets the target change over time as knowledge is gained. Unfortunately, iterative development is expensive, probably twice as expensive as waterfall for the same result: "refactoring" is another word for "rework," and there is a great deal of this in iterative development.
Agile in practice is typically waterfall without a project plan: the project sponsor knows what is desired, and when, and is trying to get it for cheap. Iterative development fixes the time taken ("timeboxing") and the cost (level of effort); what is unknown is how long it will take (or alternately how much you can put into a sprint). Starving Agile has the same result as starving typical development: you only get the 1/3 of the software that is apparent, not the 2/3 that makes that 1/3 truly functional, reliable, and maintainable.