well, for my purposes/genre it is. the Oxford is awesome, overall, but it messed with my kick drum track!
Ozone is the only limiter that did not degrade the kick (in my tests).
i have a very hot, pre-baked kick track that, even though i account for, and mix, into my mastering chain, is still pretty close to the target end-game (before it hits the chain). so, my mastering chain has to do its mojo, but still keep any pure sine wave aspects intact, while still being liberal with the transient shaping it does with stuff above 300hz. it's a tough balancing act.
i think you may be correct in that i should have put the Elephant last; Oxford is better. i think i put it 3rd as it's really good for other per-track tasks.
for me, it was a shootout between Fabfilter Pro-L and Ozone. i actually wanted to make Pro-L my go-to finalizer, but it just didn't keep the sub 250hz stuff as tight and transparent as Ozone.
yes, Ozone 5's IRC III is night and day between type II that was in version 4.
also, the fact that Kaskade and Morgan Page (two EDM producers I highly respect for their mix/mastering qualities) use Ozone, is not lost on me. but, the real proof for me was my testing -- it was all about the kick track (specifically the 25hz to 80hz range), everything else was mostly fine with the other Limiters (i actually liked the sound of PSP Xenon in many ways, too).