BMW seem to be using hybrid in a particularly useless way.
Only very high performance cars seem to have it to provide an extra kick (in this case a 335i). You can also get it in [top end] 5 and 7 series.
What I want is a hybrid unit to provide that kick [when needed] in a BMW with [relatively] modest performance (e.g. 730d, 320d). It would also (by regenerative braking) reduce fuel consumption in traffic.
Round here Stagecoach has a load of buses with the feature. They keep up with the traffic better, make less noise and use 30 - 40% less diesel.