I think multiple contracts are appropriately considered for the following reasons:
One - to be able to have the 11 month reservation advantage at different locations. We have contracts at both onsite and offsite (e.g. HH, VB) locations. This enables us to easily make reservations during peak seasons at the various locations.
Two - to have flexibility IF there is a need to sell some points. Contracts in the 100 - 200 point range seem to move faster on the resale market. I've seen large contracts hang unsold for long periods of time. If your financial situation changes, you might want to sell part of your points, but not all. You can only do this in contracts, so a 250 point contract would have to be completely sold, but you could sell one of two 150 point contracts. Also, in the unlikely event that one of the resorts was pushed out of the
DVC agreement, you would still likely have some points in a contract for a resort still in DVC. Again - flexibility.
Three - to have better ability to will or give contracts to children later in life. While I hope to still be able to use my DVC in 40 years, it may be that I won't be able to do so, and my two children would each be able to have one or more of the contracts.
IF you go with multiple contracts, I strongly recommend having the same use year for all. That greatly simplifies reservations, banking, borrowing, etc.