Ideally I would like to see six candidates in the "finals" when there are three seats to be elected. At the moment, there are already 5 candidates with >30, and Yann will get to the 30 soon too. Maybe it wouldn't be that weird to state that the required number can be raised next time?
Six candidates doesn't sound like enough to allow the smaller projects to be represented. If only candidates that can get a large number of endorsements are allowed to stand then only candidates that are known by a large number of people (ie. contribute to large projects) will be able to stand. While you can vote for someone you don't know (since you can find out about them during the election), you can't really endorse them.