I would suggest that Haiku should enter beta phase now and all new features applying to R1 be delayed to R2 if possible. The longer we wait for R1 the harder it is going to be for Haiku to be compatible with the computing requirements of its users. Once R1 has been released then work should begin on R2 by making the default GNU Compiler Collection version 4.X.
While I understand that being BE OS 5.1 compatible is important, I also believe that stagnation is a real danger here. Be OS was and still is a brilliant and wonderful OS! It had features that truly were innovative and ahead of its time. While I believe Haiku should be a reimplementation of Be OS, it should not be a mirror image of a dead OS forever!
Again I am forced to put away my love and admiration of Haiku here temporarily and look at the state of the matter! In the beginning it was and still is an admirable thing to try to preserve Be OS and it's legacy. But it has been eleven years since Be OS died and there has not yet been a R1. Here we are on the verge of a fourth Alpha release and still many bugs are yet to be fixed and missing features have yet to be developed!
My opinion is to drop all features that have been planned for R1 that have not been done and wait to do them in R2. This way we start working on a Beta 1 and hopefully within a year to two years we will have a R1! Then work can begin on R2. Depending on an antiquated gcc 2.95 is already causing problems and will continue to cause problems! There are many programs that will not compile on gcc 2.95 and having two C compilers adds extra complexity!
That is my two cents! Spend it wisely.