Of course the trains don't have to go to NY Penn for them to have ridership, would Hoboken have as much ridership as NY Penn. No, Mid-town Direct services have proven the one seat ride concept of such trains are an overwhelming success.
Now here's the problem with MOM, West Trenton, and even Lackawanna cut-off trains without additional tunnel capacity. At the first chance folks will transfer to NEC/Mid-town direct trains to Manhattan. Thus overwhelming already packed trains, I've ridden NJCL trains bound for Hoboken, and it would be no exageration when I estimate 75-85% of the riders transferred at Newark for PATH or NEC trains to Manhattan instead of riding all the way to Hoboken. Adding more trains to Hoboken is doable and would be a cost effective alternative in the short term to the new Hudson tunnels, the major problem is how to convince those riders to stay on the train all the way to Hoboken instead of getting off at Newark.
The NEC/NJCL trains to Manhattan are many times standing room only before they even reach Newark Penn, throw into that situation passengers connecting from RVL trains and the local traffic boarding at Newark to NY Penn and the situation becomes intolerable. And then there's the passengers boarding at Secaucus!.. I don't see how adding West Trenton or MOM to the mix can be doable unless those trains skip all stops on the NEC, including Newark Penn, during ruch hour on the way to Hoboken. However if you do that your cutting off the traffic heading for downtown Newark.
It's a tough situation, the Hudson tunnels should have been built a long time ago. Now, I don't know where transit in this State goes.
When taking the overcrowding into consideration it's more feasible for NJ to look at routes such as West Shore, NYSW for expansion as those would not add to the crowding on NEC/NJCL/Mid-town direct trains if they skipped Secaucus during rush hour. Even if those trains did stop at Secaucus, it would only be intolerable for the short segment into Manhattan.