You cannot win an NBA championship without a dominant big man, neither Shaq nor JO are dominant and they can't stay on the floor long enough to be an effective tandem.
A few quibbles:
1) Detroit won a championship without a dominant big man. Last season, I wouldn't call Pau Gasol "dominant", either;
2) Shaq is no less "dominant" now than he was when he played for Miami;
3) Shaq played 75 games last season, and has had a full summer to rest;
4) J.O. played 68 games last season, and sat out at least two of those games to rest for the playoffs;
5) Brad Miller played 70+ games in each of the last two seasons, and in three out of the last four.
6) Everyone's minutes will be limited to the 25 - 30 per game range.
Still, I understand taking a "wait and see" approach with the team.