I would support canceling the SE-LRT for any number of reasons and I'm not totally swayed by the logic of "we might as well build it because we can." I really can't see any major redeeming feature on this line and very little that would justify the price. Long term, it will eliminate any possibility of anything good happening on that corridor. Even replacing the subway with LRT, dumb as it is, is superior to the transfer centric crap on the table now.
There was no real reason for the City to prioritize Sheppard over Finch, and no reason why they made the entire Transit City effort contingent on one of its' weakest links. Bureaucracies often do this, coming up with one or two good ideas and taking on a whole bunch of bad ones then making the good things contingent upon the bad being funded. If Giambrone et al structured the project in such an "all or nothing" way, then that is their problem. The very idea of building something stupid along Sheppard so that a more logical line along Finch West is brain dead.
Doing nothing is usually better than doing something stupid. Sheppard East is stupid.