Another complete rewrite?

On one hand, Qt4 is quite different from Qt3, on the other hand, KDevelop3's architecture had reached the end of its lifetime, and bigger new features (such as the pretty awesome semantic highlighting that it has now, but also UI changes) would've been hard to implement.

Some developers have therefore decided to have The Big Rewrite coincide with the Qt4 Porting (KOffice and Amarok did the same, btw), others have decided to first to a pretty plain KDE4/Qt4 Port, and then start reworking the architecture. Kontact, Digikam and K3b would be example for "relatively straight-forward" ports to KDE4 architecture, with Kontact now being ported ot use Akonadi, ETA is KDE SC 4.5 this summer.

Both approaches have up- and downsides of course, what's best is usually at the discretion of the individual developers and needs to be decided on a case-by-case basis.