While it might have been good PR, I'm not sure Obama's presence would have changed much and his security arrangements may even have influenced who else could have attended. I think Biden's presence would have helped, and Holder should definitely have participated since he was already there.
But PR concerns have a way of backfiring. Apparently, Netanyahu muscled his way in once he learned that two of his political rivals would be attending. After failing to discourage Netanyahu from coming, Hollande felt compelled to invite Abbas. Bibi further upset the French by using the occasion to encourage French Jews to move to Israel. All of this political jostling and Monday morning quarterbacking does little, in my opinion, to send the message that needs sending.
I'd much rather have seen a dozen leaders from the Middle East heading the procession, and am surprised that more folks aren't focused on that missed opportunity.