I think what people don't necessarily realize is that senators (who are appointed for 30 year terms by the office of the PMO) have zero bite, sway, or legal right to actually do anything to police their own members.  They just dont hold the rights to do it.  Most senators would LOOOVE to see Don Meredith take the road out, but they are pretty powerless to do anything about it other than condemn his behaviour.  If anyone wants to be able to remove a senator, then it is up to the house of commons and yes, the provinces as well, to draft legislature that allows amendments to the constitution which would allow the crown to expel senators when deemed fit to do so.  Short of a constitutional change, there is no way to rid ourselves of poorly behaving senators.

So in truth, yes we need constitutional amendments to the senate,  and truthfully, even senators would welcome it, because from what i understand, they are tired of seeing their reputations dragged through the mud.