PR categories are "merging"? Is this a serious question?
If so, then have a read of this page first - http://www.cic.gc.ca/english/department/acts-regulations/forward-regulatory-plan/irpr-eoi.asp
This part is of particular interest:
"Express Entry will be a mandatory first step in the Federal Skilled Worker Program (FSWP), the Federal Skilled Trades Program (FSTP) and the Canadian Experience Class (CEC)."
This implies that CEC is not going to disappear with the introduction of Express Entry (and indeed, neither are the other skilled PR programs). Of course they may change the conditions of it, as they have done in the past, but there will continue to be a pathway to PR for those with Canadian work experience.