Database view on field changes in the change_request table

Hello, 

I need to generate a database view from the change_request table that captures the time stamp of when the change records moves from its process state e.g New>Assess>Authorize>Scheduled etc. 

I've tried to join change_request against tables sys_history_line & sys_history_set, but i dont think my organisation captures those field changes in those tables.

My next solution is to join against the sys_audit table, but there are too many records that impact performance.

Is there any other simple means to create this view? - We need this as a view as we will be also synching it to SNOW Mirror. 

Thanks