Offending My Tender Sensibilities -OR- OLTP on a Star Schema

We have an OLTP database and no data warehouse. We are currently
planning out a build for a data warehouse however (possibly using
Hadoop). "X" is recommending that we convert our current, normalized
OLTP database into a flattened Star Schema.

The primary rationale for this OLTP flattening is that since most of
the app calls to the database are SELECT statements, the DB should be
optimized for that. A peripheral rationale I've heard is that the
1NF-3NF database is hard to understand sometimes.

I'm not going to state what I believe. I would like to hear my
esteemed colleagues take on this situation. What would you do? What
would you say? Is there anything you would investigate? In short, what
say you?

Thanks for your time.