If assuming an average pilot, I’d switch Belial and Laevatein around, and I’d switch Shadow and M9 as well.
In terms of sheer power, I believe the ARX-8 was stronger than the Belial, but because Leonard is a Whispered, and designed it specifically to take advantage of that fact, it could do a lot more. If a non-Whispered was piloting it, they’d only be able to get a fraction of the power and abilities out of the Belial. (That’s a big reason why Al always called him a ‘cheater’)
Overall, I think it would look more like this:
ARX-8>Belial>ARX-7>Eligor>M9(post-DVMC)>Codarl (i and m)>M9(pre-DVMC)>M6>Drache>Cyclone>Mistral II>RK92
I included pre- and post-DVMC M9s to make the distinction for when the Fairy’s Eye was installed. It does make enough of a difference, since it pushes them to be better than even the LD equipped Codarl.
Anyone with a better understanding of mech stats wanna chime in? ^^