I have successfully emerged app-office/openoffice-2.3.0 with -j2. Since openoffice compiling is very time consuming and most users doesn't know about WANT_MP=yes, building openoffice on SMP systems will be at "half" speed. I'm proposing that openoffice-2.3.0 don't filter -j flags on AMD64 by default to allow a very noticeable speed increase on SMP systems.
Not going to do that, openoffice emerges sometimes with more processes, sometimes not (and I'm testing this quite often), this is way to unpredictable to be enabled by default. Whoever wants to do that still is able to do it with WANT_MP=true