Just a few random block suggestions for consideration... If they've been brought up before and/or are under consideration and/or will be implemented, my apologies.
1. Provide alignment options for blocks for the admin... the ability to left / center / right / justified align whatever's in the block.
This could be done for articles, front page items, etc., as well.
2. Provide an option in the admin area (under "Settings," I assume) to completely hide the column collapse / expand buttons and not allow the column(s) to be collapsed / expanded.
3. Provide the ability for the admin to change various images in the admin area. I was thinking along the lines of the displayed images used for all blocks; for example, the various colored dots.
4. Provide the ability for the admin to turn any block title into a customizable link. Since only certain types of blocks will allow for linking to the related page already a part of SMF/TP, it could be good to make customizable links an option. For example, they may want to link to an external site.