No, CDH4 is not meant mainly for YARN. CDH5, on the other hand, will be.
I'm not sure how you went about setting up your CDH cluster, but it's rather easy to add the MapReducev1 service, as opposed to YARN, using Cloudera Manager.
Very few companies use YARN in production, Yahoo being the most notable.
CDH4 is not YARN-centric. Cloudera includes YARN so people can have the most recent Hadoop bits accessible to them - but it's very clear on Cloudera's website that they do not recommend YARN for production.
One of the big things that CDH4 brought to the table last year was HDFSv2, and they made MRv1 compatible with it.
To install CDH4 with MRv1, see here.