Good thread this.
I have the pleasure of flying with some of these very low hours new hires, on regional aircraft too, and to be fair, our company selection procedure is very good indeed. The quality of these 155hr or so First officers is impressive. They get to fly a 28t turboprop with pleanty of gotchas built in, in some nasty weather too.
If the same selection, monitoring and testing is caried out for MPL, then I have every confidence they'll turn out just fine. A couple of years with us and you heavy boys will be glad to have some of them sat next to you too.