How feature-complete does an enhancement need to be: vertical page centering

I'm working on page-level vertical centring and think that I have a
fairly workable solution for displaying existing documents.  How
feature-complete does a new enhancement need to be in order to be merged
into master?

I think the viewing part is working very well.  It centres, bottom, and
“block” justifies nicely with all of the test documents that I have. 
Things get visually mixed up when frames are present, but that was also
true in MS Word - which had to author the document in the first place. 
I haven't experienced crashes or freezes, so the implementation should
be fairly safe.

Editing these pages also generally works as expected without
crashing/looping. As you might expect, editing a bottom or
block-justified page will mess up the moveFwd logic a bit, so that while
editing, some text might get pushed to a new page, but when re-loaded
will return back to it's original page.  So it is not WYSIWYG all the
time when editing these pages, especially with block-justify or
widow/orphan settings.

So that is where the question comes in.  The intent at this point is
mainly to provide the ability to properly display .doc/x files coming
from Word.  Is it OK to implement in master even if editing isn't
perfect?  I admit it is a bit of a hack, but seems to be working well.
The changes ONLY affect .doc/x files that already have vertical
adjustments applied to pages, so the risk of breaking most people's
documents is already very low.

Of course, once the ability to view the documents is there, there will
be calls to be able to author these documents in LO.  (Currently, only
Word can assign vertical adjustment values to the page style.)  I'll
probably begin to work in that direction if this patch is eventually
accepted, and at that point I'll need to improve the editing aspect of
the enhancement. https://gerrit.libreoffice.org/18482

Thanks,
Justin