Yes, the last one was interesting. I'm not sure I will have a good answer.
On the first one, I think you've seized on a very important structural issue, but we also can't indulge in myths. So, yes, there are platforms and there are promises and people do vote hoping their party would generally, for those who know what are in the platforms...would like to see. But people do know minority governments can happen in our current system and we've already just briefly touched on how that can be a somewhat dysfunctional way of figuring out which campaign promises do get attended to and which don't and what kinds of compromises are made.
If you have a system where people know in advance that campaign platforms do have to end up in some kind of a more compromising collegial environment, it might not be a bad idea to start pushing parties to be a bit more clear on exactly what their top priorities are, in a way that basically tells people what might happen if this party and this party start talking about a coalition government. I think there is an issue of not knowing exactly what to count on when two parties start talking together who haven't indicated in advance that they would form a coalition. In most PR systems, you do know in advance what the likely coalitions are going to be—not always—and that can play itself out in how the platforms get presented.
I wrote something recently on this. I think it is an important issue and more generally we have to be more attentive to how easily we make promises and how many promises we make in campaign platforms. I actually think we have a kind of debased electoral process right now. The platforms are too huge and too unrealistic.
On the second one, if the two can fit together and produce proportionality and there's independent merit to the majoritarian model that was being discussed, then I would never rule it out.