What came of the proposal was an improvement: three terms, and a requirement to sit out for four years before being allowed to start the clock again. That part is good, but they failed to make it retroactive, so directors who have been sitting on the Board for years/decades get an additional 12 years, which isn't a good way to inject fresh blood. As I said before, term limits have their problems and may have been misapplied elsewhere, but at the District, meaningful ones are needed.
At this point, I would vote for the ballot measure and work to get it corrected in the future, possibly through state legislation. That improves significantly upon the original proposal, which was worse than nothing. Still the lack of retroactivity is unfortunate, as is the basic decision to put this on the ballot: it should have simply been included in the legislation passed by the state on a nearly annual basis to regulate the District, saving the taxpayers 1.5 million dollars (page 2 at the link).
Update, 10/12/10: getting term limits through state legislation may not work, so we may have to look at other solutions.