According to Deprecated Features in SQL Server Replication - New Items Deprecated in SQL Server 2012:
The RMO API is deprecated. Build new applications using Transact-SQL instead
As you can see at the bottom of the document in Community Additions, there have been several people who have objected to the RMO API deprecation. <br>
Many people use the RMO API for programming the various replication agents. It would be devastating to deprecate this feature.
Using T-SQL commands and objects are not as elegant as using RMO, which can utilize the AgentCore.StatusEventHandler Delegate to get agent status immediately. Sure, invoking an agent executable can be done programmatically, however, to get feedback on an agent status, one would have to wait for the agent file to finish being written first before it could then be read to get the agent status. It is a subtle but important difference.
The ability to get agent status messages from the replication agents immediately using the RMO API is far superior to any other programmatic methods.
Please consider my request to reconsider the deprecation of the RMO API and/or open source the RMO API.