In honour of the title under my name changing from New UT Member to just UT Member I'm going to be very opinionated on this subject!
The fact is that the SELRT is the best choice for network connectivity on Sheppard East and even if the ridership is still within BRT territory on opening day it'll slowly and carefully - eventually - grow to be LRT-worthy. And also, is there any reason that a temporary BRT (painted bus lanes - Sheppard is a pretty wide road) can't be set up on Sheppard East until the LRT is constructed?
My personal favourite plan for the Sheppard Question such as it is is the existing LRT plan which if I remember correctly involved a same-platform transfer to the subway at Don Mills, with the ultimate goal of converting the Sheppard Subway tunnel to LRT operation, extending it west to Downsview, and then north to link up with the FWLRT. Toronto still needs a continuous northern crosstown line, and that's better than nothing. Certainly better than an expensive and perpetually underused extension of the hole-in-the-ground subway eastward.
Haha, your opinion is very much welcome!
I feel that there are three valid short/midterm options for Sheppard East:
1) Build BRT lanes from Consumers to McCowan, with queue jump lanes east of McCowan. West of McCowan needs full lanes, but east of there the ridership will probably be low enough that QJ will do. Obviously the west end may be a problem, but lacking the capital necessary to reconfigure/rebuild the Sheppard/404 interchange to accommodate BRT lanes, queue jump lanes heading over the 404 may be the most cost effective option.
2) Extend the subway to Victoria Park, BRT lanes from Vic Park to McCowan, queue jump lanes east of McCowan. Naturally, the BRT lanes can be completed before the subway extension, but at least then you get a semi-permanent transfer facility at Vic Park.
3) Build the SELRT, and convert the Sheppard Subway to an LRT tunnel. I've mentioned this before, but the cost of extending the subway to Downsview as a subway vs extending the line to Downsview as an LRT + doing a conversion of the existing subway to LRT is pretty much the same cost. Build a connector LRT up Dufferin to Finch to connect to the FWLRT and you have a really nice northern crosstown.
Each of those options has its pluses and its negatives. Some are technical, some are political. Option 3 will probably have to wait until Eglinton opens, because right now it's a political non-starter. Option 1 could be framed as a 'cash saving' measure, while Option 2 is a compromise with pro-subway advocates.