TODO list / why 7.0 ?

Having been away for some time I'm very anxious to see that there's a 7.0
release coming very soon. I extracted the TODO list from the CVS (latest update
February 9).  The only really really big issue as I see it is referential
integrity. This is big, I admit but why going to 7.0 for this? Or is it because
it's long overdue (MSVC and stuff)?

There are other things that must have taken a lot of work, only it's not
mainstream the same way referential integrity is (PL/Perl and more). I had
hoped to find outer joins, but look forward to the next release if it will be
there.

Maybe I missed something in the TODO list or in the fixed list, but I couldn't
find VIEWs with UNIONs, which I understand would be solved by a rewrite of the
rules system.