Hi Hunter,
Disallowing block type elements in tables was a conscious decision on our part. We strongly believe that tables should only be used to display tabular data and not layout. And when it comes to tabular data, it most likely won't have blocks.
We believe that WYSIWYG editors aren't suited for layout and should be used only for content. If you would like to dive into our reasoning, you can refer to our blog post on this topic.
If you would like to provide templates, we would suggest providing a template/layout editor of some sort and then displaying multiple SnapEditors in each defined content area. This way, SnapEditor is used only for content editing and you can have a dedicated template/layout editor. The advantage of a dedicated template/layout editor is that you can be as flexible or constricted as you want. We definitely recognize this is another piece, but we believe dedicated tools are better than a one-size-fits-all tool that does everything but doesn't do anything particularly well.
Let me know your thoughts on this.
Cheers,
Wesley