Surprisingly a modern 16 inch laptop is super comfortable. Previously I had experience with 15.6 and 14 inch Thinkpads but the new P1 gen 7 is even smaller compared to Thinkpad w520 I used many years ago. No mechanical keyboard though, lol.

Yes, you most likely will need a new bag to carry it and one more disadvantage to me is that the screen is a bit far from you, especially compared to 14 inch versions, so you need to make fonts and scaling even larger. All the rest is absolutely amazing, even the new track pad without physical buttons is much better.