No other driver supports the connect=mode option on the connect string, so we think it should be removed from the C# driver. The driver must still know what connection mode to use (direct or replicaset), but this will now be implied by the other options.

If there is more than one host or if the replicaset=name option is present then the driver will connect to a replica set. Otherwise it will connect directly to a single server.

What is lost is the ability to specify a list of hosts with connect=direct and have the driver try the servers in order until it finds one it can connect to. You can duplicate this behavior in your own code by trying a sequence of single host connection strings yourself.

This change is scheduled for some future release to allow sufficient time for comments.