Whoever is the "Oracle Support" that does the initial setup seems to think that one-size-fits-all is the solution to every application environment. Still seems to be the approach of the 1980s that if the menu comes up then the setup is complete. For all the money and hoopla it is a disappointment to have to struggle with memory issues when doing simple tasks like adding large number of partitions.
There should be an option at install time to deal with DW and OLTP environments. I dont think that the training provided for "Exadata Support" persons is adequate to make the configuration modifications. So the "user" of the Exadata is left to deal with a machine configuration suitable for "oranges" when it is really "apples" that are needed.
Once again it all boils down to how much the organization wants to own the Exadata environment. Not taking a hands-on approach to monitoring and fine tuning based on "experience" is not making the best use of the resources. But there appears to be a trend towards "leaving everything vanilla".