This is a list of problems with ODF support in KOffice 2. These issues don't have to be KOffice bugs, but may be problems in the specification or output from other apps.
14.14.1 Gradient defines the follwing gradient styles: linear, axial, radial, ellipsoid, square, and rectangular. Currently only linear, conical and radial style are supported by Qt/KOffice. Axial gradients will be converted to linear ones.
The specification doesn't define how these styles should look like.
OOo also doesn't support SVG gradients saved by KOffice.
In some case OOo saves drawing shape primitives like rectangle or ellipse as custom shape using the enhanced-geometry draw:type, in instead of using e.g. draw:rect. The ODF spec doesn't describe which primitives can be saved like this.
<draw:custom-shape draw:style-name="gr1" draw:text-style-name="P1" draw:layer="layout" svg:width="11.5cm" svg:height="9.5cm" svg:x="5.5cm" svg:y="7cm"><text:p/><draw:enhanced-geometry svg:viewBox="0 0 21600 21600" draw:glue-points="10800 0 3160 3160 0 10800 3160 18440 10800 21600 18440 18440 21600 10800 18440 3160" draw:text-areas="3200 3200 18400 18400" draw:type="ellipse"/></draw:custom-shape>
Fixed in OOo 3.0
In KOffice strokes with svg:stroke-width="0" aren't visible (following the SVG spec here). OOo display the stroke with as a 1 pixel wide line.
User requests show we want a cosmetic line that is always 1 pixel width irregardless of zoom. Svg doesn't seem to have support for it and neither does ODF. So we should request a proper way to store this behavior in ODF documents.
Shape saved by flake uses SVG transformations as specified in ODF, which OOo currently doesn't support.
KOffice saves the the rounded corners of rects with svg:rx and svg:ry (allowed by ODF 1.2). OOo doesn't support that and displays only a normal rect. Rounded corner saved by OOo can be loaded and displayed.
OASIS uses Jira for tracking bugs; 
ODF doesn't allow negative values for fo:margin-bottom.
Section 9.2.15 view box says view box is not optional.