Genuine question. I really cannot fathom why that would matter.
Edit: Also, "a lot" is a rather unhelpful metric.
That aside, as greyboy already points out, what is going to stop a competitor from creating a fake Google+ account to give that negative review? This move doesn't prevent that hypothetical from happening in any way.
"You gave AcmeFamilyPlanner 4/5 stars, Mrs Candidate - say, do you want to have a career or a family?" (Hm, of course this could help remove bad employers from your list of prospective work places ;) )
> "You gave AcmeFamilyPlanner 4/5 stars, Mrs Candidate -
> say, do you want to have a career or a family?"
Just because you can't legally discriminate based on certain things doesn't mean people don't find ways to do so anyway.
Pretend you're a school teacher with a few malicious students that have access to Google. This exposes to them what you have privately on your phone, so you're no longer going to rate apps in the ecosystem.
No reviews from me.