I would very much like to see DNS management as an option for my clients in cpanel. Most of my clients are savvy enough to need / want it, those that don't know enough about DNS won't use it.
I agree there is the possibility that a clueless client will FUBAR their zone delegations, but that is what we am here for - and provides another revenue stream and a reminder to clients why they are paying for our expert services. We currently charge additional tech support / maintenance fees for modifying / fixing our clients DNS settings where needed.
With the current cpanel setup we are forced to either charge clients for even the simplest of DNS changes, or do all DNS work for free.
At the moment I am looking into ways to provide clients with self-managed DNS outside of cpanel, but that is another cost and another system that I have to maintain.