Another vote for intense low impact.
I would love a "recovery" cardio series, as well. Steady state, low impact cardio. Maybe a strength workout targeting muscles that we all seem to have to strengthen in physical therapy (someone else already suggested this one....).
I am also all for Slow&Heavy and Gym Style 2s.
I hope these new ones have the same fun factor as the Body Blast Series. Cathe seems to really be enjoying herself---Cardio & Weights, Step, Pump,& Jump, etc. The choreography in those two, in particular, have a high fun factor, in my opinion.