The trouble with any rating is that is open to abuse. It also allows those people who manage to "grab" attention to simply get more ratings in a cycle. Popular = more ratings = more popular. What is really needed is some method to "cycle" through creations in general so unknown creators get more exposure. Removal of the downrate button does not stop this, if anything, it would enhance the problem. Ratings do not work and the cycle is also encouraged by the buddy system. It is however what we have. I don't see a way around it unless you have a system whereby you "earn" ratings or have a max "rating" limit per person allowed. Rate it or lose it and a max 10 ratings for an individuals creations per day or something. Possibly even you earn ratings by being rated. Every possible solution would cause lots of complaints though. It's an imperfect world. People just have to accept that whilst keeping their minds open how to enhance the experience for everyone and where necessary making suggestions.
It should also be noted that ratings does not equate to good in game.