You could certainly give it a shot. May shake things up for you! Not a bad idea though I personally couldn't go w/o weights for very long at all. I did Insanity and added upper body to it. I was going thru withdrawals w/o them in the very first week!
I always "feel" leaner and skinnier (meaning pants feel different) when I do cardio-only. Who knows. It works for me...But, I love to lift weights...and I know in the long run that weights are important. But, I cardio-only works for me.
