For the wildcards, I am ok with any number of them as long as this number is defined before the event and not changed during it, To cover the case of people joining late an idea could be to offer the wildcard after the qualification tournament (as in normal chess) so that everybody has to play the qualification.
For the time control, I agree with Flourish's metric but I think the time control should be the same for the qualification, candidates and final match, so I am against implementing 5 5 this year. Before switching to 5 5 we could try either 5 2 or 3 5 before, since it might be a big change going from 3 2 to 5 5.
Unrelated: Are the policies for stuff like no-show, late-show and takeback defined? I did not see rules about this