Using New Outlook on Windows for personal email, calendar, and contact management
I too am seeing hesitations in Excel. I too believe they have complex beasts they can no longer manage and really need to start over but without penalizing the customer's w/o making us take a huge step back while they work on rebuilding these apps. I'd rather have a functional app that pauses/hesitates sometimes then a hugely scaled back/down version of it that doesn't hesitate.
With their having moved most to a subscription model they don't really need to keep finding things to add to each app to justify peoples continuing to upgrade. Maybe that will prevent these rebooted versions of teh office apps from becoming over grown behemoths within 5-10 years