If you have an accident with such a modification any insurance company (at least here in switzerland) would recess you and you will have a hard time to get them pay your costs. Having a family at home and seeing some crazy behaviour on the street of others (cars, other bikes) I'm out of such modifications... if something happens your'e at your own; but we all know that already, right?I have no facts to give about the topic. So my opinion is just based on what i think.
This BMC is my first electric bike. So its just recently when i sharted to get informed about the topic. I do understand your opinion about Brose, but Shimano is a powerful company and I dont think they will give up anytime soon.
Now Bosch is an european company, German I belive. Where 1 of every 3 new bikes sold are electric. In Holland 5 of every 10. So i find obvious that Bosch had the advantage when the market in this countries started to look for an electric alternative.
In London only 1 of every 10 new bikes are electric. So, if you ask me ( i live in London) here neither shimano or bosch has strong presence. And theres a huge market and oportunity.
Shimano, japanese company has decided to get into the market where bosch has the advantage already by being from a country (and area) where the popularity of electric bikes arrived first. In Japan ( i have been there several times) electric bikes are just starting to become popular. In the USA few years ago they were unknown, even today is symbolic their Presence.
But in several reviews both Shimano and Bosch are just there fighting with similar results. And i do belive Shimano in all those countries have a lot of potential to penetrate more than Bosch.