Christ or Adventism?
Sanctuary is Christ-Centered
For certainly it is difficult to argue that the sanctuary is not Christ centered. With Chirst being representing as at least the sacrifice, common and high priest, and even the various pieces of the tabernacle. Certainly with Salvation being illustrated in the services of the Sanctuary, it is difficult to make the argument that it is not Christ centered. One could argue that over time some have turned it into a mathematical calculation only, but as sister white reminds us "the sanctuary having a decided relation to the people of God." is one of the landmarks of the movement.
The Real Problem
I think that it is not that these doctrines are less "christ-centered" but that they are more "precise and end-time focused." The Sanctuary reminds us that Christ is doing a work to take care of sin. The Sanctuary reminds us what Christ is doing now. The Sanctuary reminds us that there is a judgment going on. The Sanctuary fits into our "Great Controversy" idea. And all of this is Christ-centered, but what Christ is it?
And here is the issue, you may not agree with the picture it paints of Christ, you may not believe that this picture of Christ is true, but please stop arguing that this doctrine does no have Christ at its center. Take Christ away from the Sanctuary and you have nothing but a shell. However, put Christ back into that heavenly sanctuary and you begin to catch a glimpse of the message that God has ordained that we preach in these final days.