I don't think the back row is going to present too many problems for the Brumbies next year. The return of Pocock is a very big plus to start with. Fardy will be a loss, and so will be Smiler. Jarrad Butler has been a very good club man, but will be more easily replaced with the talent avail;able. I believe Cusack will surpass Butler in time, maybe by next year. So one more back rower looks to be what's needed, and while McCaffrey is coming in, probably, I think there will be better available on the market if either of the Rebels or Force are cut.
The bigger problem is in the backs. Hopefully CL will fill a big hole at 10/12, but the current situation with injuries to Godwin and Toua has shown that depth is a problem in the backline. Banks looks the goods at 15, but who's the backup? Wing will be Henry, Taliauli, Muirhead, Dargaville and ????Ahwong?. No 13 is Kuridrani first up but then? Smith is adequate as a late game replacement but doesn't light the game up. JJH and Jooste seem to round out the talent. Both have issues and are quite young, so still a lot of development required to be starting Super Rugby players. Hopefully, there are some moves afoot to bolster the ranks of backline players for next year.