So re: better transit for Humber Bay Shores. I don't feel like you'll ever get good, fast, reliable transit into downtown from Humber Bay Shores with the 501 streetcar. Yes, you can improve service, but it will always be slow and vulnerable to traffic. Same thing with a bus, it will always be slow, unreliable and stuck in traffic.
Yet the GO Lakeshore line is within a 15 min walk of most of the condos in the area, a GO line with all day two way 30 min service and will likely get more service in the future, and of course 15 min service with GO RER.
A station on Park Lawn would be 15 min walk from most of the condos according to google maps, and 20 min from some further east closer to the river. You could look at other options between Park Lawn and the Humber river but of course people would need a way to walk under the Gardiner from the south to reach the station.
Alternatively, good bus service to the Bloor line, or Mimico station would be a 10 min bus ride.
But yeah, if it were me personally living there right now, and if good transit to downtown were important to me, I'd consider moving. I doubt the above solutions would happen anytime soon. Adding a GO station is a long process. Personally assuming I'd want to live in Etobicoke I'd rather be near the Bloor subway.
Same with a neighbourhood like the Beaches, which I think is beautiful, I'd rather choose east Danforth to be near the subway. I don't want to be in a situation where I'd rely on taking the streetcar for long distances.