Originally Posted by JasonCSU
BMW's plan for the sedan, touring, and hatchback models is to be the odd numbered series (1, 3, 5, 7) while the coupes, convertibles, and gran coupes will be the even numbered series (2, 4, 6). The 2 series coupe and convertible are replacing the current 1 series coupes and convertibles, just as the upcoming 4 series is replacing the current 3 series coupe.
OK, this would make sense...
except they already backed-out of doing this when they introduced the Z4. They said the 3-series coupes would become the 4-series, which didn't happen, and then they introduced the 1-series coupes, which could have easily been called the 2-series if they wanted to implement the scheme you've outlined; but they didn't.