I do fault WDW because they now expect their visitors to "lock in" as they call it FP+ 60 days before they arrive; however WDW won't "lock in" their schedule. In others words WDW wants you locked into your schedule, but once they have you locked in, it is fine for them to not be locked in and make major changes. I think they should be forced to lock in their schedule at the same time the guests lock in theirs.
That said, we have been parade taping week in December many times. We avoid MK on the actual taping day. The other parks have never felt any more crowded that day. Typically, they blocked 4 days for parade taping-- Thursday through Sunday. The last day was always a tentative day in case of rain or other issues. The first day is performers, the second the parade, and then the 3rd and 4th were basically make-up days in case they had weather or other issues. I have no idea whether they will keep this kind of schedule. It seemed like in the broadcast last year there was very little parade and it did not have parade in the title. It look like this year may be the same. One year there was a lot of rain and they did tape the parade and some performers on Sunday and we were at MK. We refer to that as Jonas Brother's Sunday. That year the park was fine that morning, but the minute the taping stopped at the castle stage it was insane. I think that was directly related to the popularity of the Jonas Brothers at that time though. Adding the parade taping into your week is definitely an annoyance, but you can easily work around it and still have a great trip. I don't think you will notice any difference in the other parks (a lot of people go to MK because of the taping, not realizing it is stop/start/stop/start for hours). IF you can avoid MK on the actual parade taping day, I would do it. If you can't, MK might be a little busier on parade day, and there will be no walking down Main Street or photopass castle shots, but it should still be manageable.