Two arbiters in mongodb architecture
Your suggested configuration still allows a split-brain situation to occur. If the link between the two datacentres goes down, both arbiters will nominate their local nodes as the primary. The two DCs will continue independently, and will not be able to reform the cluster when the connection is re-established.

The ideal configuration has a single arbiter in a 3rd location. We put ours in the cloud. It's a really good use-case for that.