A couple observations.
My wife has the Motus with Bosch mid motor, i have a Carrera with a Suntour rear hub motor.
I dont get much pleasure from riding hers, it carrys you along but its smooth, benign, you dont really get any feedback.
My Carrera, it kicks in, the sensation is completely different...perhaps your previous bikes gave you a different feel, one you preferred. The Bosch system will be better quality, probably last longer...but it's different, not necessarily for the good on a personal 'feel' level.
One other thing, mine can feel 'flat', sluggish if I start an incline in the wrong gear, drop a couple gears and whoosh, away it goes. Perhaps you're labouring in the wrong gear ?