It sounds like you're invested in the company/team and/or the project or this would be a no-brainer (leave). You could try confronting the lousy manager as a gr

It sounds like you're invested in the company/team and/or the project or this would be a no-brainer (leave). You could try confronting the lousy manager as a group (if you really do all agree), and if that fails go over his/her head. Then you've done the right thing by everyone. Maybe there are even some good ideas in the new design that could be moved to the existing design to help the idiot save face (at least offer a lifeline). Confronting the manager first means he/she can't claim he/she was ambushed, no-one ever said anything, and so forth.