I think if you do English with the yarn wrapped and flick your finger instead of the big hand motion it's just as fast as Continental. (Not getting into those who are fast with the big hand motion.)
Watch Knit And Crochet Now on PBS Create, Brett Bara knits like that.
I don't know if that would help with Intarsia. I knit Continental and knit backwards when doing Intarsia. I don't change my left hand hold, I pluck the yarn with my right hand.
I bet if you did it like Brett does you could also pluck to knit backwards like I do.
Petroleum based knitter, removing that nasty oil from the ground one skein at a time.