I just 'upgraded' from JMP 8 to 11 and I hate this new interface.  I have multiple monitors, but I typically keep JMP on one of them because I have other applications open on the others.  Within JMP, I almost always end up having multiple windows (graph, tabulate, analysis) and now I keep loosing track of them.  JMP used to be  
I don't really want to see you add more options, but I really do think you should add an option where you can choose either MDI or SDI (like R has).