The main problem with the Greenford line since its cutback is the fact the connection from London is so poor. Due to the nature of the GWML, trains are very often delayed on the suburban lines and arrive at West Ealing a couple of minutes late. Due to the number of freight trains using the Greenford line, often it can't really be held until the connection arrives, so you essentially have a load of passengers running over that footbridge and down the other platform only to find there is no train. As a local to West Ealing, I have also noticed ridership has declined significantly - just after the change was introduced the arrivals at West Ealing at around 7:30am were reasonably full, but now they're less than half of that. During the off-peak you'll struggle to find more than five people on the train.
I do still think the introduction of the Hayes shuttle was worth it, especially during the peak hours. Now, they are almost always standing room only and gives a much improved service to the busy stations of Southall and Hayes & Harlington. However, the Greenford Line does seem to have a sense of neglect surrounding it, especially as the train often ends up cancelled or in the form of the run-down stations, as many other users have pointed out.
In an ideal world, what I would propose is that the Greenford Line was electrified (which I know won't happen) and then perhaps a 4-car EMU could attach to another 4-cars at West Ealing and then run through to Paddington. Of course, as TFL Rail run the services now, this won't happen.
Additionally, as the GWML is so tightly timetabled coupling at West Ealing isn't really viable. From what I've seen, Castle Bar Park is the only station which generates any sort of usage - South Greenford is in the middle of nowhere whilst with Drayton Green, the E1 bus service offers a faster alternative to Ealing Broadway and is very busy in comparison.
I understand that the Greenford Line probably won't close due to freight traffic, but if you want passenger numbers to get any higher, the stations need a makeover and perhaps the service does need to be made more attractive. I don't know how this can be achieved, maybe through an increased frequency, or perhaps instead of the Hayes shuttle making an additional Reading/Didcot service at Southall, West Ealing and Acton Main Line, or even just holding the connection a little bit more, but what we can infer is that the Greenford Line has certainly seen better days, especially since the local bus network has become far more attractive despite the traffic-filled nature of London's roads.
