Either extending the Monorail from the Newark Airport Terminals directly to Newark Penn Station
If this had been planned properly, and the monorail upgraded to what was done for JFK, then I think extending the new Airtrain to NWK Penn as well as North Broad (instead of the subway extention) would have been a great idea.
There is no way the extremely slow existing monorail would have cut it. A faster, larger capacity Airtrain would be able to make the trip from NWK to Terminal C in about 5 minutes - same time it currently takes from the EWR rail station.
There would have been several advantages:
1) no need to build a new EWR rail station.
2) all trains stop at NWK so thus far more connections. Currently there is but 1 train an hour heading south/west in the evening (454pm, 603pm, 637pm, 7pm, 735pm, 836pm - also 725 express to Princeton). NWK has 22 trains during the same period - a 3 fold increase in service would have been available.
3) service for RVL and PATH passengers.
4) Access to Acela Express - none currently stop at EWR.
5) Extending to North Broad gives access to M&E and Montclair/Boonton.
6) Increased capacity - current monorail is over taxed at times. Many times the trains are so crowded that you can't get on.