Also this whole thing is entirely based on "wouldn't that be awesome?". We have video-games for this purpose already. Giant walking robots are incredibly impractical. Until we have robots that are as agile as people they are effectively redundant, at least for large sizes. We already have far more practical versions, they are called tanks. They are very fast, maneuverable and can cross most types of terrain. All this along with having multiple weapons that can acquire and track targets at high speed while moving in all directions.
If video games were a complete replacement for real life entertainment then only video games would be used everywhere, but they aren't because real physical action is still far far better then anything a sheet of pixels can convey. Until we can make a direct spinal cortex interface anyway.
And they very specifically said this is all for an arena show, not a military tech replacement. Which is why I maintain they need to shelve the legs, slap some threads on those bodies and make the arena combat happen in full pyrotechnic glory. Do the legs once this show is paying for itself.
I also agree that tracked mechs would be the way to do it, at least for the time being. Legs might draw more attention, but something akin to a two-seater excavator with (paintball) guns is more likely to actually work.