I agree and have made similar comments in an email to eBikeMotion. The way I've attempted to get around this limitation is by using the heart rate monitor option in the eBikeMotion app. If you get a Bluetooth HR monitor thats compatible with the app AND set the app to "Override recommended MHR" you can set a high or low heart rate which will cause the assist not to kick in until that HR is exceeded. (I also have the 'Sensitivity' setting set to 10 (max)). So in other words, instead of the assist kicking in as you slow down, this would cause it to kick in as you work harder.
Its a decent idea, although the execution is not currently that great. eBikeMotion acknowledges this and they have made some improvements, but could use further refinement. Issues include: Theres only one HR level vs having a HR level for each level of assist; There is a a long unpredictable delay between the time the MHR level entered is exceeded and the assist kicks in. Also, there seems to be some short curve associated with exceeding the entered MHR. Assist starts with Level 1 but moves to
Level 3 fairly quickly (I'd say within 15 beats higher). Its also slow to cut the assist once your HR has fallen below the MHR level entered.
I try to use this feature to get assist on long hills when in a group ride and then have the assist stop has we slow at the top or are cruising lightly on a flat... it mostly works but remains somewhat unpredictable. - E