Do you really understand the Rush Hour crunch? The morning rush "hour" is 6:30 am to 9:30am. From 7:30am to 8:30 am the WTC train is so packed you frequently have to let one or two trains pass to get in one at Grove St.
Oh, really? Last week I caught a 7:30 AM train at Grove Street, and was able to get a seat
Yes, it does get busy and crowded around 8:15 - 9:15, and I've had some unpleasant commutes, but it's rare that I can't get onto a train. I have never even considered riding out to JSQ first.
The new signal system should be in operation soon, and that will allow more trains to run. They're expanding platforms to allow 10-car trains on all lines. Although I don't expect it to happen any time soon, they could switch to accordion-style cars that increase capacity by 10%.
And let's get a little perspective. We aren't in Tokyo, we don't have subway pushers. Rush hour on the PATH is definitely not fantabulous, the system definitely has problems, but it also isn't the nightmare some people claim, and isn't going to explode because one more person tries to commute during rush hour.