Toronto needs a "Vibrancy Tsar". If such a concept even exists. If not, it should.
I'm not sure the issue is having one more 'Tsar' anymore than it's one more strategy or policy or masterplan.
The reality is, all these get forgotten, sidelined, under-funded, and willfully ignored at times when it suits those in power. That's not always a malevolent thing, though it can be; but it can just as easily be ignorance, or tax increase avoidance or any number of other things at play.
What's needed is politicians who actually make a point of hiring really great people (a la Becky Katz in Transportation, Vickery Bowles at Toronto Public Library or, in the past, Andy Byford at TTC). Then actually empower them, trust them and let them do their thing with as little interference as practical. (diligent oversight yes, but meddling micro management no)
Those staff who have bold visions for what is possible, the requisite knowledge, leadership abilities and work ethic can and will make good change happen if they are allowed to do so.
Planning is no different. There's certainly room to improve policy guidelines, but a great deal is proper hiring, proper training, empowering staff, demanding accountability but granting freedom to be creative and persuasive with
developers and communities to achieve more.
The other thing is bringing in top experts to speak about solutions to problems, including industry players and to look at a range of options, not just one, so that a good answer can be found for most sites, though it may not be the same answer at every site.