There has been a lot of questions about different D3 teams lately and one school over another. Many stating that there player wanted to be on a competitive team. Since 2014 the number of bids have been somehwere around 56 teams. If you are interested in playing into the regionals and CWS, you need to understand how teams get those bids.
There are three pools:
A- Conferences that have 7 or more teams get an automatic bid. Some of these conferences have tourneys to decide others decide using the regular season winner. Usually somewhere in the low 40's. In 2014 there were 40 pool A bids.
B - All independents schools not affiliated with a conference and schools in conferences with less than 7. There are usually somewhere around 2 bids.
C - At large bids. Schools are competing nationally for these spots. Teams are ranked in there region and a committee compares these teams to decide who gets the bids. But you are only up for consideration if you are not blocked by another team in your region. if you are ranked 2 in your region and the team ranked one never gets off the board, you will not be considered.
D3baseball.com has a good explanation.
D3 CWS is not always about selecting the absolute best teams for the CWS and Regionals it is about access. Some not so good teams make it to regionals through the Pool A bid while some very Good teams stay home. SOS is an important part of the regional rankings. In some conferences and regions of the country it is very hard to develop a strong SOS, because of Geography. Many good teams end up beating up on each other or there is one very bad team in their conference that they have to play multiple times.
I hope this is useful to those looking at the D3 path.