Yes, in the Edit Filter dialog you will see many things are tied to the "Stack" of all staves in the score. I think your best bet is to copy paste in the score where you can see the impact of your time signature changes. While we are working to improve copy/paste functionality, I don't anticipate such a fundamental change would make it onto our roadmap.
Cheers, Michael Johnson VP, Professional Notation MakeMusic
Hi, Michael, well, this is such a substantial feature for professionals that I think, and correct me if I am wrong, it should be tackled with urgency!
If I want to copy paste from a draft with several issues into a fresh clean paper, when I do the old and usual "stacks selection" to bring all the metadata, I also bring the mistakes along and, no matter if you subsequently cancel all but the bars you needed to paste in the first place, all the wrong metadata remains stuck in the file, making the effort of doing a fresh new engraver useless.