Being mostly converted merchantmen, the escort carriers (CVE) were notoriously easy to sink. I'm not sure what the point of adding them to ports is. Would they be required to stay by the port, or just another free-roaming CV group? If the former, why not just put an airstrip at a port? If the latter, that's the same as adding a second CVBG to a port.
Now, I'm all for adding more ship types to the game. However, CVE's had two primary functions. First, they provided merchant convoys fighter cover and airborn ASW. If we ever get merchant fleets, then adding a CVE to the convoy, with limited plane selection, would make sense. Secondly, the CVEs were used during major landing operations, to support amphibias assaults; providing aircover and CAS. They were not fast enough to keep up with the fleet carriers, but were just fine for attacking fixed locations. Since they were cheap to build, they could be risked in litoral waters, close in shore (see the Battle of Leyte Gulf for an example). Because they were slow, they could not operate very heavily loaded a/c, and had rather limited (and vulnerable) storage for munitions and avgas.
Having said all that, another possible use for CVEs would be to actually remove the landing craft from the fleet carrier groups and build a separate amphibias assault group. The ASG would have a couple of CVE's, a couple of cruisers for fire support, and a DE screen. Each port would then have one CVBG and one ASG. It would force the fleet carriers to operate in a more realistic manner, keeping them seaward of the ASG and providing the heavy hitting from afar.
