Absolutely. In fact, for an urban area this size, Toronto is seriously lacking in long distance rapid transit. I've seen instances of people downtown perceiving Eglinton is the northern rim of the city, simply because it takes so long to get up there.
Thing is, the suburban express lines proposed would be a better fit for GO to handle in this model. The Etobicoke line is already proposed to become a regional metro in The Big Move, and the Scarborough one is to receive all day service with lobbying from Markham to turn it into a regional metro as well. The money saved from not pursuing these projects could be used to make the western leg of the Downtown line a reality, among other projects.
I'd rather have Brampton and Markham GO REX lines (or Etobicoke and Scarborough, or whatever they end up being politically correctly called) than the DRL West, personally.
The primary purpose of the DRL West is to increase access to west end neighbourhoods, and to relieve congested surface routes. While this is noble, there are many other areas in the city facing the exact same problem. The Bloor and University-Spadina subways, while well used, aren't exactly packed to the brim, so relieving them with another subway isn't an immediate need.
This is very much contrasted with the DRL East, who's primary goal is to relieve the Yonge line, which is packed to the gills. Serving the neighbourhood it's passing through is a secondary goal.
Realistically, the only 2 subway projects that are really needed right now are the B-D extension to Sheppard (mainly because of the SRT lifespan crunch), and the DRL East. Similarly, the only LRT extension (beyond the initial Transit City lines) is the Eglinton LRT to the Airport, and maybe an LRT spur to Malvern.
If there was a "priority" OneCity map being made, I would have the following projects on it:
TTC: Bloor-Danforth extension to McCowan & Sheppard, DRL East from Eglinton to University or Spadina, Eglinton LRT extension to Pearson/Renforth Gateway, Sheppard East LRT spur to Malvern.
GO: Brampton-Markham GO REX, Lakeshore GO REX
The TTC should include the latter 2 in OneCity simply for the purpose of showing them, but they should be planned, funded, and operated by GO.
EDIT: Added a map of my priorities above