In case one is incapable to keep [[BackwardCompatibility]] one needs to perform a [[Big Bang]] rewrite. Some people believe that a [[Big Bang]] is the simplest solution in any situation. Let's quote one email I have seen recently:

Ad not blocking the project momentum: This should work as even if we
call it [[Big Bang]] it should not be [[Big Bang]] in the sense that all the
people would start working on it at once. That would be just a big mess.
We should start with relatively small team merging and later add people
who would make more and more modules work.

I see this as an inventive [[newspeak]]. The '''big''' means that something huge is
about to happen. The '''bang''' means that it appears suddenly. It does not matter
whether a small groups prepares the '''bang''' in isolation. In some sense that is almost
necessary, otherwise the change would not be '''big'''.