Well, one person I know rejected a couple PhD program offers to safety schools that she realized weren't right for her and ended up doing an RA position to build up some experience. After that, she went on to apply again and got into her top choice. I don't think it is a bad idea, but you have to evaluate your application realistically and think about what parts need to be strengthened. There are a lot of ways to make yourself attractive to PhD programs, and you just have to know what they are looking for at the institutions you are pursuing, in terms of skills, stats, experiences. Find the right balance in the amount of time you are willing to spend building up your CV. Names are really unimportant unless you are working with a colleague of a POI who can vouch for you.