...dark knights for a lot of damage?
Yes , Mihile is "worth" it in my opinion.
We have pretty good damage & defense.
We have a FJ-like mobility which is better than Dark Knight's "FJ" soul rush(?)
We have high resist.
We have AFA and Roiling Soul which is basically Enrage.
However, it might be boring because starting from 3rd job you will be spamming laser while training and we are late bloomers too.
So, it depends. You can* try it out til level 100 and you dont like it, you can* always make an Ulimate Adventurer.
Hope this helped you, kinda.