I'm noticing something similar in '10. If I have a diameter dimension, it'll flip around accordingly until I mess with the leader length. Then the text remains fixed to whatever side it was on.
**Turns out there's an SPR on this very issue: SPR 452089**
This has troubled me too. Other old CAD allows intuitively dragging the leader dimension text to opposite side.
Totay I "discovered" that multijog is required, which also requires more clicks! (SWK 2011 project)
WorkFlow for jog: dimension PM, leader tab, enable multijog.
That multojog mode seemed to work that day. Now I am uncertain.
I continued to try sliding a leader dimension around with no luck in SWK 2011.
In the past it was discussed with my VAR. His SPR # is not known.
I did add a vote today for ability to change side on existing SPR 40731.
The leader dragging behaves better in SWK 2012.
This bug has been fixed for quite some time, since 2009. If you are experiencing this issue, please contact your VAR to investigate.