You are only paying one designer for the service....the winner. Please remember, The rest are not being paid for the service, they are in essence trying to guess what you need. These early attempts to guess direction will naturally lack detail.
I think what Issues is saying is that you will get better results if you direct designers. The early designs are always raw. If you hire my firm to do your logo directly you will receive very simple raw concepts meant to be developed further. Once you give direction on which concepts you prefer, you will than see more detailed versions arise. No one is going to spend hours designing something on a contest site, until they know they are moving in the right direction. That's what you were seeing. Raw concepts trying to take root. The same thing would happen in a trendy Madison Avenue Design firm. The best way to handle it is to simply eliminate the ones that you do not care for. This will pinpoint your direction, and then you will see more detail.
What you interpret as a poor design is really just a rough draft meant to attract interest. We simply do not have the hours in our days to run our businesses (outside of these sites) and give finished polished products that take hours, (inside of these sites) until we know it is worthwhile to do so.
I hope this is helpful.