Hi Guys
I understand it is very frustrating to be waiting for oath for long time. My observation is that AOR, IP, TEST DATE, DM are pretty much within acceptable time frames in most of places. Come the oath time there are large variations of time span between different offices. IRCC is the regulatory authority and not liable to disclose or explain theses delays. Most complex is security and background checks which depends on individual circumstances.
Few suggestions if IRCC can implement
1) distributing applicants in nearby areas to achieve fairly equal time span for oath invite
2) may rent bigger places and invite bigger number of applicants in high density areas
3) if resources permit, hold more oath ceremonies in densely populated areas
4) if applicants willing and give choice to travel, they may be adjusted in other areas which may be far but have feasibility to accomodate more applicants
Best of luck