I like Rasheed and think he's playing better than Perkins, but I am AGAINST him starting, and here is why:
According to 82games:
1) When Rasheed starts over Perkins, the most productive unit immediately becomes one of the most unproductive
2) When Rasheed starts over KG, the most productive unit gets worse but is still productive.
3) When Wallace plays alongside Sheldon, the lineup is one of the most produtive we've had this year.
4) When Wallace plays alongside Davis, the lineup isn't particularly productive.
This trend goes on and on... and leads to one conclusion by me:
Since Wallace does not play exclusively under the hoop on offense, he is better suited to play alongside another big man who does. As a result, when he plays alongside another shooter like KG or Davis, the team as a whole suffers. Therefore, unless you want sit KG in place of Wallace, I would advise that Wallace not start in place of Perkins (and alongside KG).