While I'm an advocate for not fixing things if they're not broken, I've been wondering why this needs to be such a big deal. The 6-series rides on a modified 5-series chassis, therefore it can be considered as a 5-series coupe. But we've forever called it the 6-series, even in its first production run decades ago, because BMW told us to call it that. Meanwhile, Mercedes had an E-coupe (which is back after being called the CLK) and an S-coupe (now the CL). If BMW called it the 5-series coupe when it first came out and then decided to call it the 6-series for this model year, you would probably be having a similar reaction. As long as the F32 looks different enough from the F30, I see no reason why it can't be called the 4-series. It makes for a better sorted product lineup anyways. To be honest, "I don't like change!" isn't a good enough reason to keep BMW developers from doing what they want.
2001 Audi A6 Allroad 2.7T (C5); 2005 Audi A6 4.2 Quattro (C6); 2005 BMW X5 4.4i (E53); 2008 BMW 535xi Sports Wagon (E61); 2011 BMW X3 xDrive35i (F25); 2009 Audi A4 3.2 Quattro Prestige (B8); 2015 Porsche Macan S (on order)