I love BMW wagons. It infuriates me to no end that they don't offer them in the US anymore and we have to make do with crap like this.
The 3-Series wagon still is offered in the U.S. (actually two generations have been offered since mine); it's just the 5 wagon that was eliminated a few years ago, and with good reason - fewer than 1,000 were sold in the last year they were available in the U.S. And there's actually some speculation that the 5 wagon might return to the U.S., but I haven't heard anything on that lately. But otherwise I agree with you wholeheartedly.
The station wagon in the US is a victim of CAFE. Station wagons are classed as cars while minivans are classed as light trucks which have a easier standard to meet.