Well, I think there is certainly a lot Israrail could do if they were interested in making a smooth experience for the airport, like fixing the schedule so its every 15-20 minutes rather than craziness like 20-20-50, or offering check-in/checked bag services like they do in HKG. (I say all this as someone who uses the train when I can, even if I'm schlepping a rollable bag).
Who knows what the new Jerusalem line will do to the LLBG train service, I'd expect the service to improve greatly in frequency but terminate in TLV rather than go to Nahariyya.