Don't know that I quite understand the "real M" argument. I think the 1m is a really good platform for a performance car, arguably more than the m3 (not trying to start a flame war, just stating an unbiased observation). The stigma associated with the m3 is a big draw for a lot of people, as it has a history for being a performance animal.
Sure the M3 gets a NA v8 which is badass, but the n54 has proven to be a very potent engine. The 1m has many of the same suspension components as the m3, on a smaller platform. For some, a fully loaded 1m makes sense more than an m3 with no options. Personally I like the 1m, and am seriously considering it as an option for my next vehicle. NA would be sweet, but a smaller platform with a twin turbo engine, m3 suspension components, LSD, bulging fenders etc. would be a very fun car.
I do have my problems with the 1m, none about the drivetrain though. Don't like the colors available. Wish I could get a grey. Also, have serious issues with the orange stitching on the interior and would have to see that in person to make a legitimate judgement call. The proportions of the 1 series looks odd at times, again I would have to see the 1m in person to really judge it.
I just don't understand the argument that it is not a real M car. True, all of the past M3s have been NA, but vehicles in general are moving in a different direction and all m cars in the future will most likely use forced induction.