should i bring my bad gladiators over lvl 11?

I got alott of gold saved for epic items should i bring my bad gladiators over lvl 11 or will they be farmed for all my gold?

I would advise you to save money for later use.
First, try and get all gladiators retired. Meaning - level 50, 1000 fights, reach Primus, over 50% winrate(it gets lower as you fight over 1000 mathces).
I would advise not to spend money on epics on normal gladiators. At least not below lvl 50. I would make exception for level 50 Main(double) hand weapon and/or offhand. That's it.
Goal should be to level up all 5 glads and retire them so you can unlock Premium slaves and dedicate your time, money and everything you got on them.

tldr: get all normal glads to retire and save money for later use, or buy lvl50 epic weapons(if you really have to spend money).