I recently used formatted Excel files for a huge catalog project. Because of style challenges, I downgraded to unformatted Excel files. And ultimately that didn’t work well enough either. So I ended up (gasp) having to copy and paste. Which yes took forever, but gave me the control I needed. So I feel your pain. The InDesign folks really need to work on this feature.

Also, I wanted to share this with you from the WordsFlow website:

Pro works with Excel (one-way)
The Pro version of WordsFlow also works with imported Excel spreadsheet files as well as Word files. You can place a spreadsheet file, then format columns/rows or individual cells, etc. in InDesign. Later, if you or someone else makes changes to the original spreadsheet, including moving around rows or columns, WordsFlow will figure out what changed, and merge in the changes without losing the formatting and edits you’ve made in InDesign.

WordsFlow Pro doesn’t support two-way workflow with Excel documents, for now. But we call it a “one and a half-way workflow,” since you can work on both sides simultaneously.