Valek Filippov contacted me about the EMF+ import and he has nice summary of WMF
import problems in OOo. I am pasting his findings:

The report will be divided to sections so I'm listing bugs 'by sections'.
OOorg 2.2.1 was used. I'm going to check with 2.3 version soon.
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Figures:
1. OOorg ignores Arc, Pie and Chord if coords were 'swapped'.
I made file in which left/right and top/bottom coords are exchanged.

2. RoundRect seems to be drawn with incorrect corner radius and line weight.

3. In PolyPolygones if there is no last closing contour line, OOorg
doesn't close it.

Pens & Brushes:
1. MS docs says that width has to be ignored for dashed lines (weird,
but MSOffice ignores dashes instead). OOorg uses both dashes and
width.
OOorg seems to scale dash/dot lengths in so way that it hard to see
line as dashed if its width is default or 1.

2.OOorg seems to ignore SetBKMode for pen (can be tested with dashed
line for example)

3. OOorg seems to ignore line Cap/Join info.
4. OOorg seems to ignore Palette colors.
5. Brush patterns and bitmap patterns is not implemented (can be
checked with fulltest.wmf from libwmf examples)
6. SetBKMode doesn't work for Brushes, SetBKColor was misinterpreted.

(so most likely SetBKMode is just ignored at all)

Fonts/Text:
1. In case of Escapement and Under/Overstriking OOorg make much longer
under/overstriking line than needed for text string.

2. 'Orientation' is interpreted as 'Escapement'
3. SetBKMode is not consistent in fulltest.wmf.
4. 'MS Symbol' encoding was not translated (can be tested with
p000001.wmf from libwmf examples).

5. I failed to test MS Cyrillic encoding translation, because OOorg
failed to open this testing file.