To be fair, I don't think those who are fans of these existing BMW lines are suggesting that the new ranges will be 'bad cars', at all. I think that what they are lamenting is that BMW is giving up its uniqueness in an effort to appeal to the homogenous mass-market which is already exceedingly well served.
If you want a 1.5-2.0L, turbocharged, transverse mounted engine driving either a front axle or a front/rear via a non-fulltime AWD setup, there are literally dozens of those on the market, often from brands who have them down to a fine art. But there was only one rear-wheel-drive, longitudinally mounted option in the entire small car market, and it's being killed off.
Which kinda leaves those who liked it feeling like they're watching their favourite food joint being bowled to build yet another fast food burger chainstore.