Wow, sounds like you missed all of the good stuff... but that's not surprising as the really good stuff is not marked or even easy to find.
I can say from personal and professional experience its well worth the extra expense of hiring a guide. There really is a huge amount on offer in Les Arcs (and the wider Paradiski area). Its a truly beautiful region and unlike the PDS the secret stuff, really is secret. Even on the well known trails you don't often meet other riders.
Shameless plug here, trailAddiciton have been operating in Les Arcs (and the wider Savoie region) for close to 15 years so we have unmatched experience of the trails there... with amazing back country and lift accessed weeks, as well as special weeks such as guided tours of the Trans-Savoie.
Check out a couple of vids here:
Yeah Destination-X is a real special area... even better that its still pretty off the radar so the trails are pristine.
Let us know what dates your looking at and we'll try and get you back there.