Looks like the service from Hamilton would be diesel, not electric, and would run express from Oakville, not Bronte.
With RER Phase II (2025-2035), maybe not.
This diagram makes this Hamiltonian dream:
A tease of a Pantograph at West Harbour!
For now, yes, West Harbour opened 3 years too early for its market (due to PanAm) and only serves 2 trains a day for Pan Am. Major ridership increases will happen once year round
NiagaraGO service begins, as West Harbour will be the only way to catch a train Hamilton-NiagaraFalls. Given the recent successful Welland Canal priority guarantee for GO Trains, I'd anticipate year-round Niagara GO service will be announced before this decade is out.
Combined with
all-day 2-way Hamilton service and local Hamilton mayoral candidates salivating at campaigning on a relatively-small electrification extension from Aldershot to Hamilton. It will likely will require at least one rail-to-rail grade separation, and also the Hamilton LRT to be built, to justify 15-minute Hamilton RER service. But it could happen politically (provincial & municipal campaigns) given Aldershot tantializingly close to West Harbour.
By then, both CN/CP will have finally gotten used to running freight trains occasionally under GO RER catenary, with sufficient enough experience to let Metrolinx electrify into Hamilton. One is bound to negotiate letting Hamilton become electrified, and there's much more unamious support for GO expansions in Hamilton's electorate, despite divided support for LRT.
I can imagine the 2026 Hamilton municipal election being "electrified" (pun).
As we speak, CN is expanding the Hamilton Junction (saw pile drivers operating there this Feb 2016) and building a Metrolinx-funded 3rd track, in their corridor, into the West Harbour GO area, anticipating the increase in GO traffic over time,
amongst other construction I've photographed last year.