I think you're definitely on to something there! A couple of suggestions, if I may:
- if you really wanted to push the Chrono Gladiator look, I think you might want to consider replacing his right arm/hand with a chainfist or a similar implement, making it look like he is really geared up for fighting -- and little else. It needn't even be another chain weapon, giving him some kind of implanted flail or whip could be equally interesting and further underline the gladiator feel.
- what about adding a broken chain to one of his legs, his hands, or someplace similar, in order to show that he can only be barely restrained between battles and has just managed to break free prior to the current one?
- you could also look at adding some small elements to his head that suggest augmetic treatments: cabling on the back of the head, drug vials and/or electrical coils on the back or arms,... Many
40k ork weapons have little washer screws as a detail. Those are easy to shave off and look really cool when glued to the head of a servitor, arco-flagellant or chrono-gladiator:
Will you only be building him, or are you going to paint him too before giving him away?