I agree that is actually one of the very few things where I think Romney's background shows he'll likely do something useful.
Cutting waste to make companies (and the Salt Lake City Olympics) viable seems to be something Romney is good at.
For me, however, abortion is a make-or-break issue. I've watched the video of Romney discussing his pro-choice views during the Massachusetts governor race. I'm originally from Michigan and I know more than I should about the Romney family history on this issue. Even if I believe Romney has changed his views and will be pro-life in his policies, I do not believe he can be trusted to pick Supreme Court nominees who, once they're confirmed and never again need to face a vote for the duration of their life, will remain consistently pro-life.
Unfortunately, we have a long and sad history of Republican presidents nominating people to the Supreme Court who turn out to be real problems once they're on the court for life. I do not believe Romney can be trusted with this responsibility.
Some will attack me for being a single-issue voter. I'm actually not — I'm a Romans 13 voter. The government has certain biblical obligations to protect its people and punish evildoers, and I'm just as adamant on the need for a strong national defense, honest justice, and similar issues as I am about abortion. However, there are few issues on which America is failing in its responsibilities as clearly as abortion. If government can't protect babies from being killed in their mother's womb, it is grotesquely failing in one of its key functions — protecting the lives of its people and upholding justice via the sword of the state to punish evildoers.