You are quite right to distinguish between trying to set legal or formal limits on the Prime Minister's prorogation powers and talking about the moral constraints. We've operated until recently on those moral constraints.
The constitutional conventions that had built up, the informal ways of doing it, and the moral expectations of it were essentially that the power of prorogation would only be used for procedural or policy agenda matters, not as a confrontation with the House of Commons. It's really just the more recent events that created this controversy that prorogation could perhaps be used to challenge the right of the House of Commons to deal with business before it. That brings us here today.
In one respect, it would be great if we did not even need to discuss this and if that moral consensus had held that prorogation should be an agenda issue rather than a power issue between the crown and the House of Commons. Ultimately, whatever route is chosen has to depend upon a moral consensus that the Prime Minister's power should not be used to confront the House or to shut down the House.
It doesn't matter whether you put it in the Standing Orders or the legislation. A very determined Prime Minister could still push this to the limit, and the ultimate protection in Canada is a moral consensus that it is wrong for the crown to use its powers in this fashion.