You haven’t told me why you dislike different sizes.
However, I see no reason why it should be mandatory.
The way I envision it, the behavior will be the following: you can switch between two modes: tabbles-with-same-size and tabbles-with-different-sizes.
1. When you switch from same-size-mode to different-size-mode, some tabbles will become bigger, and some will stay as they are; no tabble will become smaller. At the same time, all tabbles will smoothly rearrange themselves not to overlap each other. (Some tabbles, becoming bigger, will push other tabbles away; these tabbles in turn will push other tabbles, so there will be a lot of movement on the screen.)
2. when you switch from different-size-mode to same-size-mode, some tabbles will shrink and some will stay as they are. So some holes will appear that were not present previously. These holes may be annoying to you. But, if you never switch to different-size-mode, you should never see this.
What do you think?