Sure, having a 100% healthy team is more important than having HCA but I think HCA is really, really important. We've seen it last friday against LeBron & cie. I know the C's can win on the road but to win in Cleveland looks like an impossible task this season : they've lost only one game at home!
The playoffs are different from the regular season, I know, but HCA would improve by far the Celtics' chances to win a championship. With the way the refs are making calls against the C's (mostly non-calls in fact) at home, it would be a nightmare in Cleveland. However, Quicken Loans Arena put aside, I'm not worried about the Celtics's ability to win on any court, including the Lakers'.
It will be hard to get HCA now that they are trailing the Cavs by 2 games but I like the Celtics' chances... if only they are not getting other players hurt. And with the return of KG, Rondo, etc.