Beauty about our front row rotation is we have players that can slot across lock/second row/prop (for the most).
For bench rotation that's awesome.
Thing is, big backrowers tend to be less mobile in defence, I like big forwards but prefer a solid defence, backrowers and a lock that can help shut down 2nd phase play, goose steps, missed tackles, short balls, etc.
Mobile backrowers is important, especially when those big backrowers like RFM don't really do your typical prop hitups.
I'm a little iffy on RFM and some young big forwards because I find his lateral movement in previous seasons wasn't the best, that could be the previous years' team mentality though, overall they weren't playing for each other, heads down when going was tough or tough calls rather than being committed to everything and aiming up.
Defence is also more a team effort rather than solely an individual effort, so I'm hoping it was just the team mood at the time to blame, not RFM's and others fault when scrambling in defence covering tackles edges of the ruck. Fresh start, confidence, and good camaraderie can make a world of difference in regards to commitment in defence.