The higher BB will also help with pedal clearance on the road-- it's helpful at low speed in the corners on a track, but at higher speeds in turns on the road (when the bike is leaned over).

I'm not sure it's that big a deal to switch crank lengths. I ride 172.5 on the road, and 165 on the track, and probably half my mileage (and almost all my racing) is on the track. It's usually not that noticeable, and only takes a few minutes to adjust usually.