I think the evidence suggests that Hillary Clinton could have won the Democratic nomination with just a little bit more support, and probably would be governing significantly more conservatively than Obama. For one thing, given her disastrous experience with health care reform in 1993-1994, it's reasonable to assume that she would have stayed away from that issue at all costs.
I think this is mostly correct. I'm not sure Clinton would have "stayed away" from health care reform -- the issue was the centerpiece of her domestic platform, and it would have been costly to simply abandon it from the outset. I do believe, though, that any significant adversity would probably have caused her to retreat. In the wake of Scott Brown's victory, her chief political strategist, Mark Penn, urged Democrats to abandon health care reform. ("Break it down and start with the easy stuff like electronic medical records first and work up to the harder parts year after year.") That's probably the sort of strategy Clinton would have followed if she had won.