Inglis was definitely superior, but at the same time just because he got a bit injury prone, doesn't necessarily mean Mitchell will too.GI had already won a CCM as a 5/8 when he transitioned and was a superior athlete. Despite that, his body still broke down and moving from centre cost him a few years career wise. The rorters needed a FB and a 5/8 last round and LM still played centre.
Also, if the Dogs sign LM for 10 years he'll have to play past GI's current age.
EDIT: Besides, this comparison is unfair on GI. He was far superior than LM at the same age.