I was noticing that several of my category pages were taking quite a while to load, and so I came up with an alternative solution to having every post appear on the category index page. This works if you have individual archiving enabled on your site.
Category-Base and Date-Based Archive Templates
this is just the mt code for the center of the page - you'll still want your formatting outside of this!
CODE
<MTEntries>
<$MTEntryDate format="%B %e, %Y"$> - <a href="<$MTEntryLink$>#<$MTEntryID pad="1"$>"><$MTEntryTitle$></a><br>
</MTEntries>
<$MTEntryDate format="%B %e, %Y"$> - <a href="<$MTEntryLink$>#<$MTEntryID pad="1"$>"><$MTEntryTitle$></a><br>
</MTEntries>
I'm using several modifications on this code for theredkitchen and hopelessromantics, but that's the basic code that can be modified.
Hope this helps some people!
Kristine