Hey, I bought En Garde too! But while it is generic enough to be used for any pre-napoleonic historical period - or even fantasy - I guess I do not have a plan to play it like that in short horizon. Actually, I struggle to find enough time for a trivial painting, not to mention finding enough time and opponents for a proper game. (And neither do I have purchased and painted the two foundry swashbuckler warbands I crave, but that's another story.) The combat in En Garde is what I can use right now, though. It is detailed enough and allows for choices and bluff even in duel - so why not use it for gladiators?
Some changes would have to be made, however.
- Partial armour: All point costs are multiplied by six, e.g. basic Rank 1 character costs 6x4 = 24 points. This is because the armour may cover only parts of the body (expressed in sixths), and is subtracted from attack roll only on a successfull armour save roll (i.e. rolling same or under the armour coverage, combined from heaviest to lightest).
- Shields would work differently. Both parma and scutum would give a "shield token", which could be used for enhanced defence (and perhaps shield bash?), the latter would also add +1 to defence roll.
- Defender could reduce the wound score by backing off - which wouldn't gain him much popularity though...
- More ploys (shield bash, showing off, sidestep...), more weapons (net, cone, flail)
- Algorithm for audience appreciation (probably positive points for attacks, negative for defence, extra for flashy moves)
- Possible bonus for flanking?
So these are the main differences just from the top of my head. I'll try to cobble up something less vague, test it and then refine and post, but in the meantime, don't hesitate to throw your suggestions at me.