The first point is absolutely right. Smaller parties would likely become better represented, such as the Greens in Canada, because they'd get a more proportional share of seats, depending on how that works through.
How does it affect the members? This is a complicated question. For example, if you went towards a proportional system, you have to think about how would members get selected for that district. Often it can be that somebody has been placed into that position by the party leadership, so the members are actually more accountable to the leadership sometimes under a proportional system. For example, in Italy you'll get hand-picked into that ranked position.
We need to think about technical issues. If you're going to have a district which is PR, is it open or is it closed, meaning are the ranked positions selected by the parties and fixed, or can voters change them and individual members try to expand their voters' will?