Here in the UK, i have a 318i and the car is fantastic. I have only ever had four cylinder BMWs and although i would ideally love a six with its more wholesome exhaust note, that is really the only advantage for me and I can't justify the extra purchase price, fuel consumption and insurance costs for a noise. The pre LCI 318i has just about enough power and is a particularly smooth and relaxing drive, especially on the motorway - significantly better than many cars i have driven. I would rather have a lower powered BMW than another make with higher power - they are just better all round cars in my opinion (handling/styling/engineering).
Anyway, my point is this: Don't be sad that BMW could introduce four cylinders to your market, they are very excellent (and efficient) engines (the petrols/gasoline are made in the UK you know). Also, they are extremely unlikely to drop the sixes, at least for a fairly long while.