Unfortunately, the surface sections of Eglinton may well have bus-stop-style spacing, which would lead to bunching that would completely eliminate the benefit of the underground section. What's the point of a billion-dollar tunnel when the streetcars arrive at the portal in 4-vehicle clumps every 25 minutes?
I also hope against hope for a DRL, but it seems the best case scenario would be some kind of underground streetcar, limited to the capacity of the surface section on Don Mills. The current arrangement really shows that Transit City isn't really about carefully considered transit planning: the Don Mills streetcar dumps everyone on the Bloor line, adding even more pressure on Bloor-Yonge station and the Yonge line south of Bloor, the most congested points on the system. But, as Glenn de Baeremaeker says, it gets a streetcar to every councillor's ward!
The next thing they'll do is propose a billion-dollar rebuild of Bloor-Yonge station, instead of just spending the same amount on a DRL subway!