BMW disenfranchised a lot of loyalists changing the 3 coupe to the 4 series, and it just doesn't roll off the tongue the same. Still, the manual transmission is more a relic than ever - they used to be more fuel efficient and faster than an automatic transmission car - but now that is the opposite and the auto sips better and is usually faster (sometimes by a lot). Beyond that they have the advantage of torque management and generally better control of engine power/delivery - especially in high speed response applications like stability control events.
Though, it should be said Porsche also ditched the clutch pedal for their latest and greatest as well. It's incredible how far the "purists" must go for that "old fashioned" clutch. Personally, I acknowledged that the M6 would suck more gas than the A6. It'd be harder to deal with in snow. It might be harder to sell or trade in. And maybe it'd even be slower. But I didn't rightly care because it's just more fun.
That and I love how many people are shocked it's a Cadillac.... with a manual transmission.