I hear what you're saying, and I understand, but I think adcoms will know you're trying to pad your GPA if you take easy community college courses. Keep in mind, most of your competition will be people who didn't do that.
Try earning another science degree. If you have a bio degree, go for chemistry or vice versa. That way you're taking science courses that are more difficult. If you can improve your science GPA doing that, it will look much better for you. One piece of advice that I always thought was helpful when it comes to science classes, is always go more advanced, never easier. I was always told that if you get a C in a science class, instead of retaking the class, get an A in a more advanced class instead.
I don't think it has anything to do with being superficial. Again, put yourself in their shoes. You have two candidates. Same science GPA, one earned theirs taking CC classes post bac, the other one earned theirs taking graduate school science courses. Which one looks better on paper. In the end it's all about how good you look on paper before you get an interview. The competition is fierce and you don't want to do anything that will make your competitor look better for any reason.
Of course, there is the other argurment that adcoms dont have time to look at all the details in an application and will only look at the bottom line numbers before deciding to grant an interview. So who the hell knows. But you can be rest assured, once an interview is granted, most likely your application will be looked at much closer and you may get asked about the post bac CC courses. You'd have to come up with a pretty good reason, if that were the case.
Anyway, this is all my opinion. I don't know any of this for a fact. But if I were you, I would nix the CC idea.
What is your science GPA, by the way?